Fix inconsistent indentation.

Many templates had indentation where some lines were indented with tabs and others with 4 spaces, in the same file. I did a `sed -i` across all .js files containing tabs and replaced them with 4 spaces each. The result is source code which is consistently beautiful across different editors.

Note: There were a few `foo-spec.js` files which appeared to use 2 tabs for indentation on some lines. I left them alone since they weren't tabs, but they remain inconsistent with the 4-space indents everywhere else in the project.