Add support for ping command on windows in the simple node runner

It is a portable version of the realpath(1) utility that you can find on
Mac OS X and FreeBSD (see also The Open Group Base Specifications Issue
6, IEEE Std 1003.1).

Without the -P flag, pwd(1) might return different values when the
current path contains one or more symlinks, depending on how you got
into the current directory.

In simplenode.runner, this may cause PIPE_DIR to have different values
on each use, which will make it impossible to connect to the running
node unless you guess the correct path yourself.

Fix searching for plugins

If a plugin is in a dependency, rebar didn't search for it carefully
enough.

Add rebar-deps env to port compiler SharedEnv

REBAR_DEPS_DIR is often needed when a nif needs to be linked with a raw
dependency.

Travisci fixes

Do not compile nodetool escript

Since R15B02, ct_run returns a non-zero exit code when some tests
failed or were auto-skipped. (See ticket OTP-9865.)

This fix makes it so a non-0 code doesn't cause an instant failure, but
still prompts for log verification before doing so. Given the behaviour
was acceptable for pre-R15B02, it should be valid with it with
post-R15B02.

The fix should also be backwards compatible.

This removes the dependency on lib/compiler in an OTP release.

More error logging

rebar throws away some error messages, e.g. the ones generated if the yecc compiler is broken.

simplenode.reltool.config: use default sys-level mod_cond setting

Makefile: call Dialyzer with -nn flag

As discussed here
http://erlang.org/pipermail/erlang-questions/2012-December/071135.html
change the reltool spec to use the default sys-level mod_cond setting.

This allows overlay_vars to merge comma delimited var config files

This speeds up 'make dialyzer' for the common case of Erlang/OTP built
without --enable-native-libs.

Fix unicode

rebar_core: fix sub dir association

Update rebar repo urls

Change simplenode template files to work on more platforms

Support reading mustache 'lists' from files

Implement 'rebar help CMD1 CMD2' and extend common 'rebar help' msg

This commit add support for reading mustache 'lists' from files, so you
can use the list section functionality when templating things.

An example of the list syntax is as follows:

{package_commands, {list, [[{name, "riak"}], [{name, "riak-admin"}], [{name, "search-cmd"}]]}}.

Then you can, for each of the list elements, render some text:

{{#package_commands}}
chmod +x bin/{{name}}
{{/package_commands}}

* Allow the following predefined analyses :
   undefined_function_calls, undefined_functions, locals_not_used,
   exports_not_used, deprecated_function_calls, deprecated_functions

* Trap some possible errors in case module information is not
    available

* ignore_xref works on all checks and can take {M,F,A} tuples.
  (Automatic behaviour export suppression still only works on
  exports_not_used)

When developing Riak, we have found bugs and other issues due
to the number of platforms we support.

Here is an overview of the changes:
  -  Fix command-line syntax for commands to work on *BSD / Sun
  -  Add chkconfig and getpid to nodetool
  -  Replace platform specific 'kill' commands with a nodetool
	getpid method
  -  Fix RUNNER_USER settings to work on *BSD

Running tests on windows creates false positive due to setup failures
not executing all tests.  Checking for tmp_dir was failing on
subsequent runs.  Added cases to tmp_dir creation to delete preexisting
tmp_dirs in .eunit directory.

* allow plugins to print help message for implemented commands
* append core rebar.config options to common 'rebar help' message