* Save 128 byte by moving variable to stack
* Make usb mass storage buffer smaller on F2 processors and put into reuseablebuffer
- Lower USB mass storage buffer to 512 bytes per default on F2
targets, makes usb speed slightly slower ~600 kB/s instead ~700 KB/s
in my tests, saving 3584 bytes
- Save another ~300 bytes by putting that buffer into reusableBuffer
* Don't put id into reusuableBuffer
All uses of id can be on the stack as well. Makes no difference for ram usage but makes it safer to reuse reusableBuffer
* Only link cdc serial when needed
We always linked usb cdc even in non debug builds. CDC uses about ~600 byte of RAM for its buffers and structures.
