Refactor JSInterop transformer state management
Fix #192: Fully support (sane uses) of scala.Enumeration

Note that this commit adds primitives for
scala.reflect.NameTransformer.MODULE_SUFFIX_STRING and
scala.reflect.NameTransformer.NAME_JOIN_STRING since
Enumeration.toString relies on them, but they rely on the
scala.sys.props infrastructure that we do not want to implement.
Merge pull request #196 from gzm0/enumerations

Fix #192: Fully support (sane uses) of scala.Enumeration
Add missing comparison ops to js.String and fix compiler to support them
Add proxy object for java.lang.String implementations

The trait scala.scalajs.runtime.RuntimeString contains all
implementations for methods on java.lang.String. The compiler
automatically forwards calls to these methods to the trait's
implementation class.

This also fixes #164 (Implement java.lang.String.getChars)
Forward constructor on String to RuntimeString (equivalent to methods)

This also fixes #154 (Implement all String constructors)
Merge pull request #201 from gzm0/runtime-string

Forward methods on java.lang.String to dedicated implementation objects
java_lib lang.Math nextUp, nextAfter, ulp for Double
Merge pull request #198 from techaddict/test

java_lib math nextup nextafter ulp for double's
Fix #200: Enumeration fix was complaining about Enumeration implementation
Merge pull request #202 from gzm0/enumerations

Fix #200: Enumeration fix was complaining about Enumeration implementation
Fix #195: Reflective calls on primitive value types

Implement methods on Scala primitive values types in corresponding
Java boxes.
Make reflective calls on scala.Array work
Make reflective calls on js.String work
Make the path of the output of optimizeJS configurable.

Exactly in the same way that paths of the outputs of
packageXyzJS are configurable, i.e., through
(moduleName in optimizeJS), (crossTarget in optimizeJS) and
(artifactPath in optimizeJS).
Fix #204: Restrict ancestors of classes extending js.Any
Merge pull request #208 from sjrd/customize-opt-js-output

Make the path of the output of optimizeJS configurable.
Remove js.Function.apply().

Its name clashes with the meaning of apply in Scala, and call()
can be used instead with the :_* notation.
Protect receiver of reflective call from double evaluation
Merge pull request #206 from gzm0/js-any-inheritance

Fix #204: Restrict ancestors of classes extending js.Any