Don't enable receive line status interrupt for UART, we don't care.
Remove duplicate GPIO set.
Add debugging when setting baud rate on LPC17xx.
Re-organize UART init for LPC17xx to allow changing baud on the fly.
Update atcommander library to fix bugs.
Fix UART baud rate.
Remove extra log message.
Don't pre-init UART before setting baud rate.
Temp. enable auto-rts when setting baud rate.

What's insufficient with our manual setup?
Re-add a slight delay to allow RN-4x to boot up before setting baud.