Adding external methods for efficiency feature
Applied formatting fixes from master branch and added external-methods file to build process
Added building efficiency stuff, more stats, fixed some stats, moved audio files into project repo
Merge branch 'feature-efficiency'

Conflicts:
	src/bookmarklet.js
v1.5.0 release - Added building efficiency stats and indicators, added option to show efficiency table, moved audio files into Git repo, enhanced some stats, added effective CpS method and used it in all relevant stats calculations, fixed some stats accuracy, minor visual fixes and tweaks