To avoid treating plugins' info/2 functions as commands, we catch calls
to 'rebar info'. Previously (4b8c81fb) we simply printed the help
string, but it's much more informative to print the following:
Command 'info' not understood or not applicable

inttest/rgen_1: double the timeout a second time

Clean up rebar.config.script

Added a library template.

bootstrap: avoid trying to run 'debug' command

rebar_dia_compiler: fix Dialyzer warnings

If you invoke 'make debug', then bootstrap executes rebar:main/1 with
the extra argument "debug" and rebar treats that as a command. There is
no such command.

Without this patch you will see the following on bootstrap:
Command 'debug' not understood or not applicable

60s still seems to be too low, as it timed out for at least the R15B01
job of the timeout patch merge:
https://travis-ci.org/rebar/rebar/builds/15051701
https://travis-ci.org/rebar/rebar/jobs/15051703

Fix log levels

inttest/rgen1: increase retest timeout (30s -> 60s)

The current default (30s) causes inttest/rgen1 to timeout too often. Add
retest.config to double the timeout.

Make list of commands (for unabbreviation) easier to maintain

It's easier to modify the list with each command on a separate line.
The shell completion scripts have already been modified that way.

Switch retest dep to upstream (dizzyd/retest.git)

Now that Dave has merged all patches, it's safe to switch back to
upstream retest.

rebar_core: fix Dialyzer warning introduced in aa46d85 (#157)

Fix false reporting of (plain) vsn strings

Add missing dep examples and fix existing ones

Fix erl_opts use

Previous generate-upgrade required renames in rel/ directory:

    rebar generate
    ...changing code...
    mv rel/<release> rel/<release_prev>
    rebar generate
    rebar generate-upgrade previous_release=<release_prev>

With the proposed changes you can now do the same without moving things:

    rebar generate # default target dir: rel/<release>
    ...changing code...
    rebar generate target_dir=<release_new>
    rebar generate-upgrade target_dir=<release_new> previous_release=<release>

Delete unused inttest/retest binary

Avoid getting erl_opts twice in test_compile/3, and make sure the
correctly filtered (platform_define, etc.) version is used.

rebar used to mistakenly report plain version strings like
{vsn, "1.0.0"} as follows:
DEBUG: vcs_vsn: Unknown VCS atom in vsn field: "1.0.0"

Properly detect unknown/unsupported version terms and abort
if we encounter one.

While at it, rename a variable in vcs_vsn/3 to be non-misleading.

As discussed with Martin Schut, remove support for
{app_name, "vsn", {fossil, "url", latest}.

Fixes for #137 and #142

Don't over-aggressively clean the code path in the presence of lib_dir directives

Fix update-deps with certain forms of the {tag, ...} type

Init RUNNER_SCRIPT var in simplenode.runner

RUNNER_SCRIPT variable is not initialized in simplenode.runner and it's
referenced when calling sudo.

Rebar, when it encounters a lib_dir directive, caches the current code
path, adds the libdir(s) and returns the cached copy of the path. When
rebar has finished processing that directory, it restores the cached
path. This is problematic in the below scenario:

        /(lib_dir)->G
  A -> B -> C -> D -> E
   \-> F -> D -> E

When rebar is finished processing B, it restores the code path to what
it was before it processed B, removing C, D, E and G from the code path.
This means when it comes to process F, neither D or E are in the code
path, so any header includes, rebar plugins or parse transforms will not
be in the code path. Without the lib_dir directive, rebar does no code
path cleanups, so everything works fine.

This change makes rebar only remove the explicit lib_dir code paths it
added and adds an inttest that replicates the above scenario.

Sometimes tags like 1.1-3-g3af5478 or d20b53f0 are encountered. The
first is the output of 'git describe', and the second is just a regular
git SHA. git fetch --tags will not pull these down, so do a full git
fetch instead.

* fix Dialyzer warning
* fix formatting