Updated StringReplacer.quotedSplit() to accept more than one quote char.
Allow USB product and manufacturer strings to be supplied in boards.txt
boards.txt: Refactor the default usb build flags into a generic property in platform.txt
Fix whitespace (tabify), oops
Remove hardcoded product names (all provided for in boards.txt)
Added quoting to usb_product key to preserve double quotes.
See #1422.