add grouping files passed on to subprocesses
unified shell handling code
move shellescape to shell handling code
improved extra_grep
remove unneded array from debuger patter
Add test for user supplied rubocop flags
Implement user supplied flags for rubocop check

Fixes #175
Update changelog.md
Add test for failure with user supplied rubocop flags
Merge pull request #183 from padde/user-supplied-rubocop-flags

User supplied rubocop flags
The local check prefers underscored file names.

We used to look for a local check script in `config/pre-commit.rb`.
All of the dashes generally come from Git's usage of the `pre-commit`
hook.

However, not everyone uses dashes in their filenames. The local check
will now look for (and prefer `config/pre_commit.rb` over
`config/pre-commit.rb`)
Merge pull request #184 from jish/josh/local_check_prefers_underscores

The local check prefers underscored file names.
autoresolve git root without calling any commands, fix #186
Merge pull request #146 from jish/bugfix/avoid_long_command_line_gh_146

Breaks with E2Big if too many files are committed
Merge branch 'master' into feature/unified_shell_handling

Conflicts:
	lib/plugins/pre_commit/checks/coffeelint.rb
	lib/plugins/pre_commit/checks/scss_lint.rb
	lib/pre-commit/checks/grep.rb
Merge pull request #181 from jish/feature/unified_shell_handling

improved shell handling
Merge branch 'master' into features/consistent_output_error_gh_119, updated after #146 and #181

Conflicts:
	lib/pre-commit/checks/grep.rb