Sourcemap highlighting.

Synchronize highlighting of the transcoded tokens to the
cursor on the input tokens in repl.html.

Implement SourceMapRanger to aid in sourcemap uses.
Refactor repl-module to extract 'replOptions' module

Review URL: https://github.com/google/traceur-compiler/pull/879

Closes #879.
Require System in feature tests to set up globals as side-effect

TBR

Review URL: https://github.com/google/traceur-compiler/pull/895

Closes #895.
traceur@0.0.32
add base class
Merge branch 'master' into await-expression

Conflicts:
	bin/traceur.js
Add back old tests