Improved the handling of trunkPath

- $this->baseUrl is only used if $this->trunkPath === false, otherwise
we will use $this->baseUrl with $this->trunkPath.
- scanning through trunkPath will now look for composer.json file
instead of a path that matches $this->trunkPath, beacuse checking
against the latter failed with deeper trunkPaths
- $this->rootIdentifier is now 'trunk' no matter how deep
$this->trunkPath is (with deeper trunkPaths, the name became something
like "dev-trunk-devel-team-packages-package"
Fixed a coding style issue

Missing a space between if and (
Fix for #2739 (and #1755), added support for directory excludes in the .gitignore file like /directory or directory/
Updated the regexp and added more test cases.
Updated the regexp and added an other test case for sub dirs
Add autoload support for .hh files (HHVM)

HHVM is adding support for an alternative extension for files using
HHVM-specific features. Support them in the Class Map and PSR4
autoloaders.

Trivial example: https://github.com/fredemmott/hh_extension_toolset
Only look for .hh files at runtime if using HHVM

The ClassMap generator will look regardless, but that's not a runtime
cost, so seems desirable (in case composer install/update needs to be
called with php5 for some resaon)
Merge pull request #2769 from sndpl/issue/2739

Fix for #2739 (and #1755), added support for directory excludes in the gitignore file
Fix for #2557, added missing run-scripts
Fixed some docblocks
Separated the scripts events in 2 arrays because they need to be called by different dispatchers.
Update code to latest EventDispatcher, refs #2722
Merge pull request #2268 from schmkr/svnDriver-trunkPath-improvements

Improved the handling of trunkPath
Merge remote-tracking branch 'fredemmott/hh-support'
CS fixes, refs #2823