bumped version to 2.1
add service provider interface
updated CHANGELOG
moved lib/ to src/
removed the bootstrap file for tests
updated docs for 2.1
removed obsolete @package annotations
created a sub-namespaces for Fixtures in tests
feature #124 add service provider interface (dominikzogg, fabpot)

This PR was merged into the 2.0.x-dev branch.

Discussion
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add service provider interface

finished #123

Commits
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fd6ab9a created a sub-namespaces for Fixtures in tests
32b79eb removed obsolete @package annotations
0ab4f51 updated docs for 2.1
c67c27a removed the bootstrap file for tests
40b099a moved lib/ to src/
a895667 updated CHANGELOG
9b769de add service provider interface
a8625ba bumped version to 2.1