Support for long click and pressed state

Based on code from AbsListView, added support for long press so that an
onItemLongClickListener will be called for a long press on cards, and
added the pressed state for cards when they are clicked or long-clicked.
Added checks for motionPosition >= 0

Added checks to verify that motionPosition is not negative
Added long press handler to sample

Added onItemLongClickListener with a toast to the StaggeredGridActivity
sample.
Properly detect the orientation of the device.

When the keyboard is shown the gridview will improperly
think the device is in landscape.
Removed conflicting fix

Removed a conflicting fix that had already been made on the Etsy master
Merge pull request #88 from jstralko/master

Properly detech the orientation of the device.
Build updates to support Android Studio 0.8.1, Gradle 1.12, Plugin 0.12, BuildTools 20.0.0 & custom maven release fork to support plugin 0.12
Simplified isLandscape() call
Merge pull request #98 from DougSimonton/master

Support for long click and pressed state