perf(compiler): An option to disable the ElementProbe.

Closes #1118
Closes #1131
feat(benchmark): add automatic gc before each test

Also included is a script to launch Chrome Canary with the appropriate flag to
enable manual garbage collection.
docs(developer): fix typo in developer.md

Changed instance of "xhange" to "change"
feat(platform): Make angular invoke web_component polyfills for browsers without native web_component implementations.