Update gradle version (Android Studio 0.6.0)
Update build tools version (Android Studio 0.6.0)
Update gradle-mvn-push for gradle 0.11+.

This hasn't been fixed in mainline gradle-mvn-push, so referencing the following commit from a PR that looks like it will be merged:

https://github.com/shamanland/gradle-mvn-push/commit/cc18d56549cdea03f744b6fff27911569394073e
https://github.com/chrisbanes/gradle-mvn-push/pull/29
https://github.com/chrisbanes/gradle-mvn-push/issues/28
Typo
Add OnStickyHeaderScrollOffsetChangedListener, allowing header appearance changes based on scroll position.
Add resizing headers to sample project to demonstrate OnStickyHeaderScrollOffsetChangedListener.
Temporarily switch to normal TextView due to flicker of underline on first resize.
Update README