Move array iterator polyfill to its own module

This is based on the V8 implementation which was originallyu done by
yours truly.

Review URL: https://github.com/google/traceur-compiler/pull/578

Closes #578.
Self-documenting names for internals in modules.js

Review URL: https://github.com/google/traceur-compiler/pull/580

Closes #580.
Remove all uses of Project, Compiler, ProgramTransformer and related classes.

All uses of Project replaced by Loader.
Files Project, Compiler, etc deleted.

TBR=johnjbarton

Review URL: https://github.com/google/traceur-compiler/pull/586

Closes #586.
Rename CodeLoader to std. name Loader; module-loader.js to Loader.js

TBR=johnjbarton

Review URL: https://github.com/google/traceur-compiler/pull/590

Closes #590.