Update to distinguish from release
README.rst: update to note support for msp430-elf
sensors/sht21: major review and cleanup

Correct the bit used to identify the heater in the configuration.  Add
infrastructure to read both temperature and humidity in a single
blocking call, as supported for BMP180 interface.  Extend example to
perform diagnostic: enable heater, monitor sensor, disable heater,
monitor sensor.  Use EIC values to determine whether HTU21D or SHT21 is
being used.  Document and work around HTU21D I2C bus instabilities.  Fix
issues with persistent error on no-hold-master I2C bus policy.

Tested on both SHT21 and HTU21D.
sensors/bmp180: refactor to simplify extending test cases
sensors/bmp180: add test case and fix for overflow

AC1 is unsigned, and for a given BMP180 instance its value was large
enough that the intermediate scaling operation set the high bit,
resulting in a negative value where a non-negative one was anticipated.
Fix by explicitly using signed long.
exp430f5529/fatfs: vet against R0.10b and display version in banner
cleanup: distinguish libc variants

In preparation for proper newlib support add the pieces necessary to
tell who supplies the basic functionality: msp430-libc (mspgcc) or
newlib (msp430-elf) possibly augmented by embtextf.
msp430-elf: work around bug in _disable_interrupts()

Current TI-provided intrinsics fail to implement the standard behavior
for the _disable_interrupts() intrinsic, producing an assembly-time
warning from the toolchain and incorrect behavior relative to other
toolchains.

See: http://e2e.ti.com/support/microcontrollers/msp430/f/166/t/348108.aspx
utility/event: add new module

Derived from work on radio state machines, this new capability supports
ordered timestamped events with associated data, as well as simple edge
and level triggered signals.
examples/event: show execution statistics

Display number of times each MUX alarm interrupt fired and the active
main-loop duty cycle.
unittest: support 64-bit integer comparisons
timer: support reading full-precision times and correcting them

As we start to do more with NTP, having the full-precision available
only as a 32-bit low and 16-bit overflow counter is inconvenient.
Provide a way to return the 48-bit counter as a 64-bit integer.

Also provide a way to adjust that value so that a full-precision
representation of a timestamp captured in hardware as a 16-bit counter
has the correct corresponding setting for the upper 48 bits regardless
of subsequent overflow (so long as the 16-bit counter did not lap
itself).
port: expand SET_REN macros to no-ops when REN not supported

This eliminates conditional code in applications, at a cost of not
notifying the developer when REN functionality is absent.
serial: add facility to get bus/baud rate
timer: support reading counter for mux timer base
utility/event: add periodic event support

There's a common need to do things periodically; don't make every
application code its own infrastructure for doing so.  This version only
supports event tags, not event flags, as it passes the configuration
data for the periodic event in the event record.
eui64: add uint64_t access to EUI64
utility/event: refine description of periodic event fields

A casual reader might think it possible to change the interval to stop
repetition after the next event.  While theoretically this might be
useful, it's best not to mutate the values of fields read in an ISR, so
disallow it.  Implement timely processing of the event and cancel it
there, or use a non-event muxalarm callback.
utility/uptime: add routine for human-readable scaled time

For displaying a wide range of durations it's nicer to convert ticks to
something smaller and understandable.
core: include stdbool.h

We already require C99 for various anonymous struct/union types, so go
ahead and use stdbool as well.