Add skip_deps=AppListSeparatedByCommas feature.

I agree it's a bit of a weird thing, but it's a reasonable and safe extension. When time comes to properly overhaul stuff, skip_deps should disappear entirely.

Add zsh completion script

This allows `rebar ct suites=abc` to consider all suites when
you have a rebar setup with multiple sub_dirs.

Previously, rebar halted after it could not find the suite in the
first dir. But the suite might be present in another dir (when
sub_dirs contains multiple dirs).

This commit makes it so instead of halting, it prints a warning and
continues with looking for the suite in the other `sub_dir`s.

Note -- This uses try/catch to cause the test to be skipped because
otherwise I needed to adjust the return values of 4 functions, the
code path is pretty deeply nested here. Otherwise the whole call chain
needed to be adjusted for this return value:

`run_test -> make_cmd -> get_suites -> find_suite_path`

IMHO, I think for exceptional cases like this it is fine to use throw;
specially since only the {skip} is catched and nothing else.

For enable to shell-completion in zsh.

Add support for minimum OTP versions

Revert arch string changes

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

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.