Update README.md to include example build task

Resolves #251. Hoping this helps others understand that usemin won't run the concat/cssmin/uglify tasks for you.
Fix <img src> not being replaced when followed by ng-src
Merge pull request #342 from tedjp/ng-src

Fix <img src> not being replaced when followed by ng-src
Merge pull request #311 from zfarrell/readme-add-task-example

Update README.md to include example build task
Update README.md.
Add JSCS support.

Also move style checks from JSHint to JSCS.
Fix JSCS issues and make everything more readable and consistent.