docs(guide/$location) remove duplicate 'Crawling your app' section

The "Crawling your app" section was duplicated.
I just removed the duplication and moved the section to the 'Caveats' section.

Closes #7244
perf($interpolate): optimize value stringification

previously we stringified numbers via toJson which was expensive, I optimized
the code so that toJson is invoked only if really necessary

Closes #7501
docs(guide): correct order of directive arguments within the animations chapter

Closes #7482