Loader.module() should resolve to a module

Review URL: https://github.com/google/traceur-compiler/pull/698

Closes #698.
Update semver to 0.0.15 and publish.

This needs be the last step in normal workflow.
TBR=@arv

Review URL: https://github.com/google/traceur-compiler/pull/703

Closes #703.
Add tests for side effects for import {} from name

Expanded test for #701

Review URL: https://github.com/google/traceur-compiler/pull/705

Closes #705.
Fix typo in comment
Build traceur-runtime.js with package name traceur-runtime.

Fixes #701, Polyfills not included in bin/traceur-runtime.js.
Distinct package name ensures that, while compiling the runtime, we won't mix
input files with traceur modules precompiled in the compiler.
Add test for bin/traceur-runtime.js including polyfill module.
Fix up System object initialization to allow browser test/runtime.html to run.

Review URL: https://github.com/google/traceur-compiler/pull/706

Closes #706, closes #701.
Merge remote-tracking branch 'origin/master' into generator-use-try-stack-runtime

Conflicts:
	bin/traceur.js
Code review cleanup