Update gpio_api.c

Modified gpio_set() to allow PIO0_0, PIO0_10, and PIO0_15 to be properly configured for GPIO.
Changed LED mapping to RGB

Changed the pin mapping for LED1, LED2, and LED3, to Red, Green, and Blue respectively. This matches the KL25Z and LPC11U68, and makes more sense in my opinion.
Update gpio_api.c

Modified gpio_set() to allow PIO0_0, PIO0_10, and PIO0_15 to be properly configured for GPIO.
Merge pull request #321 from neilt6/master

[LPC11UXX ] gpio_api.c - pin expansion