5.3 Migration to Flex 4.12.1 completed.

Everything works. Compiles. No warnings. No runtime exceptions.
All samples run successfully from ant and AirMonkey.

The used Flex SDK version was generated for Flash Builder using
the \ide\flashbuilder\makeApacheFlexForIDE script.
Moved to flexunit 4.2.
Generated ant tests for say_hello_web and say_hello_air.
Patched all ant scripts.