Fix STM32F1 and F3 USB device driver.  It was not handling NULL packets correctly and it prevent use of the driver with the CDC/ACM class
Optimize request buffer sizes in the serial USB drivers so that we avoid so many NULL packets and so that the OUT request buffer size is exactly the max packet size.
Upate .gitignore files.  Add .dSYM. Make sure / is present where needed.  Add some missing .gitignore files
.dSYM only needs to be in the same .gitignore files as .exe
The Makefile in every directory that can generate a .dSYM should also clean .dSYM files
Fix that way that NxWight UnitTests are reigistered as NSH builtin apps
Add NSRF42L01 driver.  From Laurent Latil
 Fix nRF24L01+ driver integration for the STM32 Tiny.  From Laurent Latil.
Add NRF24L01 terminal example.  From Laurent Latil.
Added transitional tools to gitignore
Updated defconfig, now 100% vetted vs. old config AND KConfig clean
KConfig fixes for STM32F4 (fixes flash prefetch never being enabled, added two NSH options to KConfig)
Merge branch 'kconfig_fixes' into integration