Merge branch 'release' into development
Rename LIB_DIR constant in FF_LIB_DIR

... in order to avoid clashes with other libraries.
Make Curl dependency optional

An object implementing CurlInterface now only has to be given to request
factories if they should NOT use PHP's cURL module - i.e. only when cURL
should be stubbed.
Update changelog
Update documentation for release 1.0.0-beta.7
Merge branch 'release'

* release:
  Update documentation for release 1.0.0-beta.7
  Update changelog
  Make Curl dependency optional
  Rename LIB_DIR constant in FF_LIB_DIR
Update documentation for release 1.0.0-beta.7
Merge branch 'release'

* release:
  Update documentation for release 1.0.0-beta.7
Update documentation for release 1.0.0-beta.7
Merge branch 'release'

* release:
  Update documentation for release 1.0.0-beta.7