Go back to previous dir after compiling

There is a `process.chdir` happening in `recursiveModuleCompileToSingleFile` that should be reverted once the operation has been completed.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1290

Closes #1290.
Fixes unit test on recursiveModuleCompile

This removes previous assertion and adds a new test to check for current working directory being the same after recursive compiling.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1292

Closes #1292.
Remove Promise.cast; update Promise.resolve

A while ago Promise.resolve took on Promise.cast's behavior, and Promise.cast then died. This bit me pretty hard today when switching between Node 0.11's promises (for which that change is present) and Traceur's under Node 0.10 (which still have the old resolve).

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1293

Closes #1293.
Add metadata property to Loader function calls.

Pass options on metadata.traceurOptions.
This aligns us with spec changes for metadata and with es6-module-loader.

Refactor InternalLoader.load/load_ to simplify calls.
Clean up some error-usability issues from MultipleErrors change.

TBR=@arv

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1289

Closes #1289.
0.0.59
Add support for Unicode escape sequences (\u{123})

Fixes #371
Partial sync up to changes in compat-table format.

Still a few cases which are incorrectly analyzed.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1303

Closes #1303.
moved rsvp to dependencies
0.0.60
Fix bug with too aggressive Unicode escape sequences

Fixes #1308
Reorg TraceurLoader along the lines outline in es-discuss.

Loader: interface with spec functions .import(), .module().
Loader impl is InternalLoader. InternalLoader focused on dependencies.
TraceurLoader extends Loader implements normalize/locate/fetch.
InternalLoader uses Loader interface for .normalize() et al.
InternalLoader uses new LoaderCompiler,  internal API for Loader to Compiler.
(Renamed LoaderHooks -> LoaderCompiler, no longer related to es6 'hooks').
Remove obsolete InterceptOutputLoaderCompiler and repl.js.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1302

Closes #1302.