Ignore remote errors in parsing Mercurial log

Summary:
This probably indicates some none fatal error, e.g.:

> remote: Certificate invalid: name is not a listed principal

The best thing here would be to avoid the error but we shouldn't explode even if it is there.
I tried to mute the error from the output but didn't find a switch or config option to do it.

Test Plan:
  $ hg outgoing --branch default --style default

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5267
Minor, fix `arc land` for the case of no dependencies.

Auditors: Afaque_Hussain
Improve the description of using `arc land --revision`

Summary: The message suggests that only one revision would land.

Test Plan: Read it.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5277
Initialize variable in lint patch output
Dispatch an event in arc land right before pushing a revision

Summary: I looked at the pros & cons at adding hooks in git/hg vs arc land and I prefer arc land.

Test Plan:
* added an event listener and made sure I could handle the event.
* made sure things get reverted when the event handler throws an exception.

Reviewers: vrana, epriestley, pieter

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5268
Improve Windows compatibility

Test Plan:
  $ arc liberate
  $ arc lint

Reviewers: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5319
Compute lint cache key before linting

Summary: If user changes the file contents during linting (usually when prompted to apply a patch) then we save the old messages to the new file contents. Fix that by computing the hash before linting (or after applying patch).

Test Plan: Changed the file during linting, verified that the file hash didn't change.

Reviewers: epriestley

Reviewed By: epriestley

CC: ptarjan, aran, Korvin

Differential Revision: https://secure.phabricator.com/D5320
Merge branch 'master' of http://github.com/facebook/arcanist