NORDIC can now reset using serial break
Merge branch 'master' of https://github.com/mbedmicro/mbed
Added PwmOut for LPC1549 target
Protection against concurrent access to USBHost

Fixed regression: Protection against concurrent access to USBHost using
locking class
Use Lock class within USBHost
Merge pull request #201 from toyowata/master

Added PwmOut for LPC1549 target
Merge pull request #202 from donatieng/master

Protection against concurrent access to USBHost