Fix major misthink in Cortex-M0 port:  The Cortex-M0 has no BASEPRI register.  We have to revert to using the nasty PRIMASK register

Convert olimex-lpc17stk configuration to use the kconfig-frontends tools; Fix some compile errors in the pl2303 USB device driver

Fixes to the LM4F clock configuration.  Errors in register handling caused everything to run at half speed

LPC17xx GPIO interrupt fixes: lpc17_setintedge() must be atomic.  Can't disable interrupts from interrupt handlers because they are automatically re-enabled.  Try re-configuring pin instead.