Enable call-through by default for unshadowed classes and methods.

Remove shadows for TextUtils, and the various SpannableString classes.
Don't blow up on theme attr references.
Add ShadowCanvas#setBitmap.
Better support for projects without app manifests.
Merge branch 'xian/call-through-on-unshadowed'

* xian/call-through-on-unshadowed:
  Better support for projects without app manifests.
  Add ShadowCanvas#setBitmap.
  Don't blow up on theme attr references.
  Enable call-through by default for unshadowed classes and methods.