Removed separate compilers
Resolves apps to build
Finds avail deps before pulling/building
Includes relx
Simplifies build commands

If you happen to fetch a zip archive of the git repo and try to build
from that, you may, for example, ask erlc to build src/._rebar.erl.
._* are OS X resource forks and not real .erl files. This may also
happen with network filesystems on OS X. To fix that, limit the
files compiled by rebar to include only those which start with
a letter or a digit.

As mentioned in the OTP documentation, licensed customers may use
patched OTP installations where the otp_patch_apply tool adds a '**'
suffix as a flag saying the system consists of application versions from
multiple OTP versions. When we get such a version string, we drop the
suffix, as we cannot obtain relevant information from it as far as
tooling is concerned.

ensure any processes with a reference to an old user process as their
group leader are updated to use the new user process. this introduces a
slight delay at startup as the system must wait for the new processes
to be registered. there is a max wait period of three seconds (before
the shell command gives up and throws a timeout error)

fixes #314 ("rebar shell" somehow blocks using io:format in gen_server
handle_call)

* fix overlong lines
* where appropriate use %% instead of %

Moves ct_extra_params to the end of the generated ct_run command.
This allows users to pass commands to the underlying emulator
using -erl_args. The included rt test demonstrates that it is
possible to pass an addtional option to ct_run and -erl_args at
the same time. Finally, the test executes in regular and verbose
modes because rebar constructs the ct_run command differently in
verbose mode.

This reverts commit 07e2232847baa634b7d09bdb87dafda6c6bcc4a4, reversing
changes made to 37cf470ae9.

Partially revert naming changes introduced in 93689703c1:
CoverageModules -> FilteredModules
get_coverage_modules -> get_matching_modules

Having the name "coverage" meaning "filtered/selected modules" can be
confused with code coverage.

- Use `cover' with QuickCheck testing
- Reuse the `cover_*' rebar.config options
- Refactor cover-related code to separate module (`qc_cover_utils')
  for use with both `eunit' and `qc'

This reverts commit 3297ffec2c89c6b7135165b4bfaeaeb07167c33c, reversing
changes made to 0401debb3c.

* Corrected regexp: `[x|y]` -> `[xy]`.
* Used an re:replace/4 option instead of multiple IOlist functions.