Got everything set up (new/modified files)

- Added g_switch_flag in k_process
- Included initialization for timer and uart_irq in k_rtx_init
NOTE: some timer stuff, I just commented out for now, feel like it goes
elsewhere in code
- Changed uart_polling to use UART1 for polling, as expected
- Added timer.c, timer.h
- Added uart.h, uart_def.h, uart_irq.c
- Removed our old (broken) user test procs, just using Irene's for now