When a DTL template includes other template files, those files don't need
to be compiled separately, and therefore can be given an extension different
from `source_ext` (such as `.dtli`) to avoid being compiled.  This fix
allows rebar to find included dependencies with names `*.dtl*` rather
than `*.dtl` and properly determine if a template file needs to be recompiled.

Handle the case where the error didn't occur in the file being
compiled.  That is, if there is an error on line 9 of bar.hrl,
instead of:

/path/to/foo.erl:9: type foo() already defined

print:

/path/to/bar.hrl:9: type foo() already defined

The printed message is made more terse.

Example before applying patch:

    ERROR: Compiling template src/view/test.dtl failed:
      {error,{"src/view/test.dtl",
              [{{4,7},
                erlydtl_parser,
                ["syntax error before: ",["\"\\\"HELLO_WORLD\\\"\""]]}]}}

Example after applying patch:

    ERROR: Compiling template "src/cmp_html_error_template.dtl" failed:
        (line:3, col:12): ["syntax error before: ",["trans"]]

Added a backward compartible feature to specify `erlydtl_opts' options
for the DTL template compiler to allow inclusion of templates in different
directories with different compilation settings for each. E.g.:

    {erlydtl_opts, [
          [{doc_root, "src/view"}, {module_ext, "_dtl_vw"}]
        , [{doc_root, "src"},      {module_ext, ""}, {recursive, false}]

        , {out_dir,   "ebin"}
        , {compiler_options, [verbose, debug_info]}
    ]}.

The definition above is identical to this (the last two options
are duplicated in each list):

    {erlydtl_opts, [
          [{doc_root,   "src/view"}
          ,{module_ext, "_dtl_vw"}
          ,{out_dir,    "ebin"}
          ,{compiler_options, [verbose, debug_info]}]

        , [{doc_root,   "src"}
          ,{module_ext, ""}
          ,{out_dir,    "ebin"}
          ,{compiler_options, [verbose, debug_info]}
          ,{recursive, false}]
    ]}.

In this case "src/view" and "src" directories containing template files
will be compiled.  A new `recursive' option tells rebar_erlydtl_compiler
to search files recursively from a given doc_root.  In the example above
the "src" directory won't be scanned recursively, and the target template
name for target beam modules won't have "_dtl_vw" suffix.

Add support for non-Erlang/OTP (raw) dependencies

Fix return value of rebar_overlay

Add hostname variable to reltool overlay templates

When 'rebar overlay' is run rebar_core got a wrong result
{Config, ok} from rebar_reltool instead of {ok, Config}.

Introduce a new 'raw' option for dependency specs in rebar.config file.
For example:

{deps,
    {dependency_name, "1.0.*",
	 {git, "<...>", {branch, "master"}},
	 [raw]
    }
]}.

When this option is specified, rebar does not require the dependency to
have a standard Erlang/OTP layout which assumes presence of either
"src/dependency_name.app.src" or "ebin/dependency_name.app" files.

'raw' dependencies can still contain 'rebar.config' and even can have
the proper OTP directory layout, but they won't be compiled.

Only a subset of rebar commands will be executed on the 'raw'
subdirectories:

	get-deps, update-deps, check-deps, list-deps and delete-deps.

Restore previous 'git describe' behaviour as discussed here:
http://lists.basho.com/pipermail/rebar_lists.basho.com/2012-September/001713.html

Document availability of rsync for fetching deps in rebar.config.sample

It was previously possible to run `rebar compile deps_dir=/path/to/deps`,
but as of 70d27c5720331076f52e4fd7bcd1dc8045c8c86a, it was nixed.

This change fixes #310.

This allows an <app-name>.app.src.script to be defined and evaluated
when <app-name>.app.src or <app-name>.app are loaded. This allows the
user to add project specific manipulations to app metadata.

By default protobuffs doesn't create beams with debug info.  This
causes issues when running dialyzer which requires debug info.  Read
the `erl_opts` config and pass it down to protobuffs compiler.

The DirRef in the spec file is relative to the directory where the spec
file is located. ct2_rt was erroneously copying the spec file to test/.

eunit_test:function_wrapper/2 was renamed to eunit:mf_wrapper/2 in
R15B02. Ignore both calls like we do with escript:foldl/3.

Cover gets slower and slower for each application. This is due to the
cover_server internal state. Stopping the cover server between
eunit+cover runs, emptying the cover_server state, gives a ~5-6x speed
improvement when analyzing many Erlang modules. Stopping the cover
server replaces the earlier practice of doing a cover:reset before each
run. On a project consisting of 62 dependencies with a total of 1866
Erlang modules the running time of rebar eunit decreased from ~20
minutes to ~3 minutes.