Make sure we don't receive an EXIT message from the dependency tracker

It pollutes IEx and scripts execution

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Fixed grammar and wrong word (exit, not exist) in Process.exit/2 documentation.
Merge pull request #1273 from rnowling/master

Fixed grammar and wrong word (exit, not exist) in Process.exit/2 documentation.
Use proper path separator in msys

For now, we are only checking the path on msys but
we may need to check it for cygwin too.

Thanks to @ToJans for providing guidance and debug
information to sort this issue out.
Use = instead of == on shell comparison
Raise proper warnings when default clauses from different definitions collide, closes #1244
Emit warning for 'x in []' in guards
Merge pull request #1275 from ericmj/elixir-in-warning

Emit warning for 'x in []' in guards
Warn on undefined module attributes, closes #963
Get rid of unused variable warning
Add -f option to make clean_exbeam
Update CHANGELOG
Validate eval options, closes #1238
Add `binding/0` and `binding/1` for retrieving bindings
Catch invalid arguments for binding/1
Some IO tests return alternate error codes on windows

Now these tests allow different kinds of error codes. However, I currently
duplicate the is_io_error? method; I would assume there would be an easier
way to do this; maybe just put it in a namespace and reference the
namespace?
Merge pull request #1277 from ToJans/WindowsBugfixing

Some IO tests return alternate error codes on windows
Use regex on matching on some of File exceptions
cp_r should pinpoint place of failure on errors
Fixed a bug within File.rm_rf on windows