firmware: factor out checking if it's a read (+35 bytes XRAM). Note: this reduces code size by 36 bytes, but allocates an extra byte of data

firmware: factor out superset bmRequestType check (+116 bytes XRAM). Everything that handle_pending_usb_setup() does has to be either: USB_RECIP_DEVICE|USB_TYPE_VENDOR|USB_DIR_IN or: USB_RECIP_DEVICE|USB_TYPE_VENDOR|USB_DIR_OUT Checking these two conditions again and again wastes memory

firmware: move factored-out ep0 stall to end of fn (+13 bytes XRAM).

firmware: remove unnecessary check (+25 bytes XRAM). Note: on the _set_ side the check cannot be removed, because it also affects the MFR_ALERT_MASK register

firmware: optimize code size by using goto (+59 bytes XRAM).

manual: develop/firmware: add note to fedora tab about path

firmware: optimize code size using bit access for IO (+33 bytes XRAM).

manual: develop/firmware: add the package 'libusb1' to the fedora dependencies. Looks like fedora doesn't automatically pull in the libusb1 package if the python bindings are installed

docs: Complete list of firmware build dependencies I have tested all three install commands in docker containers for each of those systems. Note that at the moment on fedora:latest it doesn't build because the name of the "sdcc" executable is "sdcc-sdcc". Fedora can be made to build by running `ln -s /usr/bin/sdcc-sdcc /usr/bin/sdcc` Not sure if we should mention that in the documentation, or make the libfx2 makefile autodetect it.

applet.program.ice40_sram: modify to use port groups