Cache stopped paths in lint

Summary:
If linter with file cache granularity stops linting then we don't run it on the same path next time.
But we still run linters with non-file cache granularity causing that they run even on the paths that would be stopped otherwise.

Test Plan:
Put global granularity linter after Generated linter.
Caused an error from this linter but in ignored path.
Verified that 'stopped' is saved in `lint-cache.json`.
Linted the same files second time, verified that the path is still skipped (wasn't before).

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4446
Fix whitespace around else
Include real PEP8 version and options in lint cache key

Summary: This should be done for all external and configurable linters.

Test Plan: Linted file with lint problems, changed options, relinted.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4475
Allow pht(<<<HEREDOC ... HEREDOC)

Summary: Don't raise lint on heredoc literals.

Test Plan: Linted pht() + heredoc in D4477.

Reviewers: vrana, btrahan

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4478
Merge branch 'master' of http://github.com/facebook/arcanist