added docs on the slideshow block
typo
be more specific about the template overriding
Cleanup according to feedback from @dantleech - thank you
corrected format for subtitles
corrected link syntax
added sections about imagine and rendering the slideshow
Merge remote-tracking branch 'origin/master' into slideshow_docs
cleanup after refactorings, cs fixes
Merge branch 'master' into slideshow_docs

Conflicts:
	bundles/block.rst
	bundles/block/types.rst
separate imagine block doc and provide some examples, cleanups
Merge pull request #104 from symfony-cmf/slideshow_docs

added docs on the slideshow block