Simplify ClosableLazy

* Fix the type annotation so that null is a subtype of T
* Use a closure to handle closing rather than a special member type
Prevent ClosableLazy deadlock when get is called during close

Fixes #2986.
fix deprecation warnings in build files
Anorm refactoring
Update to twirl 1.0.1
Merge pull request #2959 from cchantep/anorm-refact

Anorm refactoring
Merge pull request #3011 from pvlugter/twirl-1.0.1

Update to twirl 1.0.1
Merge branch 'fix-warning-build-file' of github.com:xuwei-k/Play20
Merge pull request #2993 from richdougherty/closable-lazy-deadlock

Simplify ClosableLazy and prevent deadlock
Merge remote-tracking branch: upstream/master