implement strip optimizer (removes unused classdefs / functions), except for the handling of "instanceof"
add method that resets the optimizecommand stash
in strip optimizer, always reset the stash so that it could be applied more than once (the usage will be to first apply it to reduce the size of the code that needs to be optimized, perform other optimizations, and then re-apply the strip optimizer to remove functions that become no longer being used)
Merge branch 'master' into kazuho/experiments/strip
add tests
[strip] preserve all methods that have the same signature as non-final native methods (since they might get called from native)
refactor (for clarification)
remove unused native classes with nativesource
Merge branch 'master' into kazuho/experiments/strip
run "strip" optimizer if --minify
autogenerated default constructor should inherit __export__ from class
do not remove native class with source if any of its static properties are used
add test covering prev. commit
Merge branch 'master' into kazuho/experiments/strip
add failing test
[strip] preserve target class of as and instanceof expressions
Merge branch 'kazuho/experiments/strip'