add .gitkeep to build folder
add changelog, closes #50
add @thewunder to CONTRIBUTORS.md [skip ci]
add newline character to .gitignore eof
remove unused use statement
add alternative default value argument to AnnotationsBag::get + tests
update some docblocks
add sensiolabs fancy badge [skip ci]
tweak phpunit config with processUncoveredFilesFromWhitelist="true"
remove dead code
add @​api docblock tag to public interfaces, interfaces without this tag should not be implemented
update AnnotationsBagInteface::get method with formalized $default argument
add hhvm-nightly to CI config