microphone and comments icons were not on the right
using guess-content-type for audio video image etc files

fixes #1768
fixes #1674 #1768 #1359

can display images in spreadsheet app now, as well as other related data etc
jshint
using mime which supports browserify
upload from audio recording is working client side

fixes #1769 fixes #1608 fixes #1698 fixes #1485 fixes #949  for #1282
updating audio video directive tests
adding recordmp3js as a depenancy of core and spreadsheet

so that it will load the workers from the relative path