extract some generally useful code from ModRef
Code to compute transitive lexical accesses of methods.

The TransitiveLexicalAccesses class computes the lexical variables
read by a CGNode and its transitive callees.  Also, a basic test case.
add support for lexical writes
renamed classes to make relationship to mod-ref analysis clearer
javadoc
organize imports
publicize method makeClasspath().  deprecate quoteStringIfNeeded()
1) added InstanceKey.getCreation sites and its implementations
2) fixes for issues with keys representing dynamic properties
  i) all properties are converted to strings, in an approximation of JS
semantics
3) fix to handling of instance keys representing numbers in binary +;
now it understands that adding constant keys of type Number requires
adding a non-constant Number key to the lval
added date-property.js
small Javadoc fix
Merge branch 'lexical-access-info'
test fix
javadoc