merged branch igorw/composer (PR #691)

Commits
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72d3c19 [composer] Add branch alias for dev-master, adjust some other things

Discussion
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[composer] Add branch alias for dev-master, adjust some other things

* branch alias allows installation of dev-master by requiring 1.7.*, which is important since most packages depend on twig "<2.0.0"
* remove the version field, the version is determined by branch names and tags only
* change license to BSD-3, this is more explicit and the preferred format for BSD licenses