registry of transport handlers

LegacyPackageHandler register for 'unknown' transport type
Merge branch 'package-loader-etc' into requirejs-wip
fix parser generation; correct AMD header
boot.js dependencies simplified
boot, smalltalk, nil, _st have explicit IDs
amberc now loads and runs with requirejs

output still does not run, define missing
hacked amberc so it now compiles and runs tests