Alle phpBB Dateien sind GPL v2 nicht nur die für phpBB3

Fix #52
Rename license.txt to LICENSE

That's also what the validator wants to have

Fix #52
Merge pull request #53 from nickvergessen/issue/52

Issue/52

* nickvergessen/issue/52:
  Rename license.txt to LICENSE
  Alle phpBB Dateien sind GPL v2 nicht nur die für phpBB3
Add language pack validator to composer.json and run it on travis
Move LICENSE files in place
Merge pull request #62 from nickvergessen/issue/61

Add language pack validator to composer.json and run it on travis

* nickvergessen/issue/61:
  Move LICENSE files in place
  Add language pack validator to composer.json and run it on travis
Add phing as dependency
Update translation validator to 1.3.6
Merge pull request #66 from nickvergessen/update-translation-validator

Update translation validator to 1.3.6
Merge branch 'develop-olympus' of github.com:phpbb-de/phpbb-translation into develop-olympus
Add phing as dependency
Add build script to generate the lang archives
Add build tasks for de_x_sie
Use git archive + phings UnzipTask
Use phing to check for lint
Remove hardcoded "release-" to allow packaging of HEAD and develop-*
Use phing on travis
Fix phing project name and validator call for non-windows
Remove parallel
Run de and de-x-sie builds separatly so we can run both and fail correctly