store file sorting options in the browser's LocalStorage
Set default instance name to empty string
New option to sort gcode files by size, reverted former utc "fix" (doesn't work anymore, works without the fix, I have no idea...), added adjusted modernizr,  delete metadata from old gcode file version when adding a new one
Merge branch 'daprice-sorting_persistence' into devel

Conflicts:
	octoprint/static/js/ui.js