gdb: change gdb remote packet size from 2048 to 1024

The mspdebug gdb remote server is much happier with 1024
msp430 timer: update timer maps (micro, 32k), documentation, add x5 micro
msp430 adc: update docs, PLUS works (x5).
msp430 usci: add DEFINABLE atomic protection for low level x5 usci-v2
msp430 usci: put atomic block around configuration.
add UartByte.{send,receive}Avail definitions for UartByte interface
msp430/x5/usci-v2: cleanup Msp430UsciUartP

- clean up comments
- replace various register access with direct calls for the function
  Usci.setIe(UCRXIE) -> Usci.enableRxIntr
- reorganize some of the code.  Easier to read.
2520: fix compiler warnings for status and various vars
2520: capturedTime overflow computation needs to be 32 cast
2520: put initilization code inside atomic to force better optimization
mm5s: update mm5s/hardware/buttons files.   nothing major
mm5s: add various radio packet files
mm5s: bring in simple panic and PLATFORM interface for mm5s
mm5s/clock: update/cleanup PlatformClockP
mm5s/battery: bring in modules for reading Batt Voltage
mm5s/2520: bring in 2520 radio implementation for mm5s
mm5s: updated hardware notes, add correct pin assignments
mm5s/pins: update hardware.h, add critical inititialzation for few pins.

o update hardware.h to reflect initial state
o add initialization for cc_resetn, cc_vreg_en, and cc_cs_n to make
  sure we don't drive the h/w nuts.
2520: cleanup of CC2520DriverLayerP

- remove redundant disables before enableRisingEdges
- clean up comments
msp430: GpioCapture needs to insist the input pin is configured for input