* Use new native packaging abstractions for windows mappings.
* Update universal sbt script to be cygwin friendly
* Modify sbt.bat for universal layout
* Fix some stty icanon (no)echo bugs in launcher script.
* No set XYZ arguments allowed. BAAD sbt practice.
* No longer swaps launcher. New SBT launchers can handle old SBT.
* SBT script now uses sbt-launch-lib.bash.