Add `String.prototype.repeat` polyfill

http://mths.be/repeat
Improve `String.prototype.codePointAt` polyfill

This patch adds the `CheckObjectCoercible` step that was previously missing.

Review URL: https://github.com/google/traceur-compiler/pull/560

Closes #560.
Fix `String.prototype` polyfills

Ref. #562.
Rename RequireJs and NodeJs transformers and options

The options are now cjs and amd.

The transformers are now AmdTransformer and CjsModuleTransformer.

Fixes #547
Replace Project with Loader in repl.html

Adds InterceptOutputLoaderHooks module for grabbing transcoded source and map.
Changes Loader.evalAsync() to Loader.module(source, options) closer to spec.
Adds name to Loader.eval() calls, as proposed in https://github.com/jorendorff/js-loaders/issues/82.

Review URL: https://github.com/google/traceur-compiler/pull/564

Closes #564.
Remove assertThrows and use assert.throw instead
Fix error in parsing Arguments

Make sure we do not allow trailing commas in arguments.

Fixes #570
WebLoader.load -> webLoader.load; similarly nodeLoader and fileLoader.

The load methods do not use 'this' and can be simply functions.

Review URL: https://github.com/google/traceur-compiler/pull/575

Closes #575.
Replace WebPageProject in runner.html with new WebPageTranscoder

Loader based testing rather than Project based.

Review URL: https://github.com/google/traceur-compiler/pull/573

Closes #573.
Add test for static methods in export/import

Works for me

Review URL: https://github.com/google/traceur-compiler/pull/574

Closes #574.
Increment npm version
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.
Rename file System.js to LoaderHooks.js

Review URL: https://github.com/google/traceur-compiler/pull/596

Closes #596.
updates link to REPL

Review URL: https://github.com/google/traceur-compiler/pull/597

Review URL: https://github.com/google/traceur-compiler/pull/599

Closes #599, closes #597.
Fix node-front-end build rules and build/dep.mk

Build intermediate traceur.js with last-good node front.
./traceur combines bin/traceur.js with src/node code.
While self-compiling, we use last-known good bin/traceur.js
from git and now we use last-known good src/node.

Emit the build/dep.mk makefile rules in evalCodeUnit() step.
Don't automatically make build/dep.mk, its dependencies are too
complex.

Review URL: https://github.com/google/traceur-compiler/pull/600

Closes #600.
Move ad-hoc CodeUnit properties into .data object

TBR=johnjbarton

Review URL: https://github.com/google/traceur-compiler/pull/601

Closes #601.
Refactor Loader to not touch ModuleSymbol; better API

Propagate to ModuleVisitor family.
Rename 'module' to 'moduleSymbol' when referencing ModuleSymbol objects.

TBR=johnjbarton

Review URL: https://github.com/google/traceur-compiler/pull/602

Closes #602.