Add support for parsing diffs, created by PhpStorm

See https://secure.phabricator.com/T4698
Don't create ".orig" files when invoking "arc patch" command for SVN working copies

See https://secure.phabricator.com/T6424
Enhance "arc diff" command with "--cl" option for SVN changelist selection

See https://secure.phabricator.com/T6437
Answering "N" to external change prompt will include externals in created diff

See https://secure.phabricator.com/T6446
Support files in "svn:externals" property in SVN 1.6+ working copies

See https://secure.phabricator.com/T6447
Automatically populate "Jira Issues" field from commit message

See https://secure.phabricator.com/T6451
erge branches 'T4698-phpstorm-patch-support', 'T6424-no-orig-files-on-svn-patching', 'T6437-svn-changelist-support', 'T6446-svn-external-in-patches', 'T6447-files-in-svn-externals' and 'T6451-auto-detect-jira-issues'

* T4698-phpstorm-patch-support:
  Add support for parsing diffs, created by PhpStorm

* T6424-no-orig-files-on-svn-patching:
  Don't create ".orig" files when invoking "arc patch" command for SVN working copies

* T6437-svn-changelist-support:
  Enhance "arc diff" command with "--cl" option for SVN changelist selection

* T6446-svn-external-in-patches:
  Answering "N" to external change prompt will include externals in created diff

* T6447-files-in-svn-externals:
  Support files in "svn:externals" property in SVN 1.6+ working copies

* T6451-auto-detect-jira-issues:
  Automatically populate "Jira Issues" field from commit message