doc: fix doxygen group for cc2538 memory map
doc: add documentation for packet format in mc1322x
doc: order the main modules in a more sensible way
doc: remove superfluous and erroneous @file params
doc: don't use defgroup and addtogroup
doc: cleanup for radio_driver
doc: put rpl_storing header to right doxygen group
doc: add or move module description where missing
core: introduce `msg_sent_by_int()`

msg_send_int() sets `m->sender_pid = target_pid`. This was used to flag a
message as having been sent by an ISR.

This PR introduces a static inline function `msg_sent_by_int()` and a
specific define for this purpose.
tests: remove do-while(0) blocks for netdev tests or comment on them
Merge pull request #2154 from authmillenon/tests/cq/remove-do-while-0

tests: remove do-while(0) blocks for netdev tests or comment on them
x86: Fix `make term` for BOARD=qemu-i386

Fixes #2184.

QEMU has changed its command line arguments.
Robust use of TimerA for 'hwtimer' module
Use TimerB for 'hwtimer' module implementation
Use custom assembly code instead of MSP GCC primitives for dINT()/eINT()
and all other functions that enable or disable interrupts
Ensure interrupts are enabled before going in low-power mode
Ensure only GIE bit is touched in splx_()
Merge pull request #1791 from Kijewski/msg_send_int-typo

core: introduce `msg_sent_by_int()`
Merge pull request #1113 from rousselk/msp430-use-timerB

Use Timer B on MSP430 architecture
cpu/lpc1768: fixed UART PCLK selection