Fix targetSdkVersion, make resize mode a flag, delayed dexopt, easy ApplicationInfo.

- Fix a bug where targetSdkVersion could not be set if minSdkVersion.  Stupid, stupid.
  Also make sure to fail if minSdkVersion is for a code name.  Really stupid.

- Change the API for resize compatibility mode to be a bit in the flags field, instead
  of a separate boolean.

- Implement delayed dexopting, to avoid the looong full dexopt during boot.  This is
  only enabled for "eng" builds.  When in this mode, the activity manager will make
  sure that a dexopt has been done before loading an .apk into a process, and will
  try to avoid displaying ANRs if they are due to the dexopt causing some operation
  to take longer than it normally would (though I make no guarantees about this
  totally working).

- Add API to Context to get the ApplicationInfo for its package, for easy access to
  things like targetSdkVersion.