Including:
- An API to opt out of Int/StringDefs generation on per-field basis
- A way to customize Builder
- Non-optional fields are passed in Builder constructor
- Various adjustments to SampleDataclass examples, as requested
Test: . $ANDROID_BUILD_TOP/frameworks/base/tests/Codegen/runTest.sh
Change-Id: I32d2eec52f05d505ff07779d923e4793d3036579