Added features to CAB
LIB: Added a CardGridArrayMultiChoiceAdapter
Demo: Added an example with cardGrid and CAB
Added stroke to CircleDrawable example in demo #67
Updated copyright
Merge branch 'dev' of https://github.com/gabrielemariotti/cardslib into dev
Added doc CardGrid in multichoicemode
Added comment to GridGPlayCABFragment
Fixed doc on cardgrid
First (raw) GridStaggeredCard
Fixed artifact id for extra
Improved card checkable on grid with CAB
Fixed issue on CAB and grid/list
Allow header popup menu to be customized dynamically

Sometime the header popup menu are dynamic according to the content of
the card. This commit allow the menu to be customized after being
inflated. The menu object is passed to the listener, which can be
specified after creating the header object.
Merge pull request #76 from xcompass/dynamic_popup

Allow header popup menu to be customized dynamically
Changed the return type of onPreparePopupMenu #76
Updated doc with the CardArrayMultiChoiceAdapter
DEMO: added an example with a dynamic popup menu, updated doc.
DEMO: Fixed doc on CardList Example
Moved gradle to 1.10 and gradle-plugin 0.8