Fix handling of repository name in 'rbt status'

'rbt status' was still using the old config.get() method of pulling out the
repository name, which no longer works.

Testing Done:
Checked with pylint, test with some internal repos that can only be identified
by name.

Reviewed at https://reviews.reviewboard.org/r/5731/
Fix perforce options access.

Not all rbt commands add the perforce command-line options, but the p4client
was accessing them as if they did. Trivial fix.
Switch to fuzzy search in setup-repo to match repository path.

Sometimes repository path on reviewboard server and on local copy of repository
may contains slight difference (trailing slash, user credentials, etc.) Now rbt
setup-repo offers repository with closest path to local path.

Testing done: Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/5724/
Merge branch 'release-0.6.x'
Fix plumbing of --disable-proxy/ENABLE_PROXY

We had a command-line flag and config setting to disable use of HTTP(s)
proxies, but it wasn't properly plumbed through to the API transport.

Testing done:
* Ran unit tests.
* Added some debug code to check that the value was getting through correctly.

Reviewed at https://reviews.reviewboard.org/r/5747/
Use the C.UTF-8 locale for executing subprocesses.

A while back, we changed our environment for executing subprocesses from
en_US.UTF-8 to C, because not everyone has a US English locale installed on
their machine. This broke subversion diffs when filenames or the diffs
contained unicode characters. Using the C.UTF-8 locale fixes this.

Testing done:
Had someone who was encountering this issue try the code change, and they
reported that it's fixed.

Reviewed at https://reviews.reviewboard.org/r/5752/
Fix problems with "key=" lines in hgrc files.

The code that parses hgrc was assuming that all key=value lines had a non-empty
value. This failed if the config included lines that didn't.

Testing done:
Created an hgrc file with this configuration and ran rbtools commands. Saw that
the bug reproduced before the change and didn't after.

Reviewed at https://reviews.reviewboard.org/r/5748/
Revert the changes to the subprocess locales.

We originally used 'en_US.UTF-8' as the locale for executing subprocesses.
After a bug report from someone who didn't have the en_US locale on their
system, we changed it to 'C', but that broke non-ASCII commit messages with
SVN. The third try, 'C.UTF-8' isn't well supported (yet). Overall, it seems
like our original choice, 'en_US.UTF-8' is the best (least worst) of these.

Ideally this would be override-able in the config file, but the execute()
method doesn't yet have the plumbing to do this. I've added a comment to this
effect.

Testing done: Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/5772/
Fix diffing for submitted Perforce changelists.

Somewhere in my diff refactoring, a couple crucial lines for diffing the files
for edited files in submitted changelists got deleted. Trivial fix.

Fixes bug 3335.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	rbtools/commands/setup_repo.py
	rbtools/utils/process.py