Miscellaneous code improvements.

Remove query ? string from Font Awesome CSS - as per Google PageSpeed
recommendation regarding proxy caching.
Prettify Grunt.js and custom.js
Clean up custom.js - apply strict mode, fix jslint errors
Move analytics code to external file.
Turn on browser caching in .htaccess now that we have applied version
control in our Grunt workflow with filename hashing.
Applied further jslint recommendations

Only one jslint error now remaining.
Some code is not very elegant - must look at refining.