* Remove unnecessary IS_COMMAND definition in clueboard/66/rev4
* Replace keyboard_report->mods with get_mods() in IS_COMMAND definitions
* Update docs to use get_mods() instead of keyboard_report->mods
* Replace keyboard_report->mods with get_mods() in tmk_core/protocol/usb_hid/test
For some reason, this occurrence used KB_LSHIFT and KB_RSHIFT, which don't exist
* Replace keyboard_report->mods with get_mods() in Massdrop keyboards (as per @patrickmt)
