Fix improper continuation at end of macro
close #71: correct misuse of underscore in identifiers

Following command plus review and reversion where change was wrong or
incomplete:

  git grep -l 'define.*\b_[^_]\w*' \
    | xargs sed -i -r -e '/^#define/s@\b_([^_]\w+)\b@\1_@g'
close #64: remove unnecessary @def annotations

For the record: the only place @def is required is when there are multiple
related macros that have alternative definitions and for convenience the
definitions are grouped within preprocessor conditionals.  Then it's
necessary to associate the documentation with the name because the next
macro to be defined might not be the one that was just documented.

Turns out BSP430 doesn't have any of those cases.
close #70: review oscillator fault code

Code correctly noted that fault bits were read-only.  Updated documentation
to note that reliance on crystal should be disabled when fault is detected
to avoid subsequent unstable behavior.
close #74: add API for port REN control

Minimal value added here, probably mostly as internal documentation of what
the REN/OUT combinations mean.  Still, adding this found a couple cases
where resistor configuration did not match documented intent.
close #73: ensure REN cleared on peripheral pins

Avoid various chip errata and undefined behavior when resistor logic is
enabled for pins in their peripheral role.
port: distinguish secondary selection architectures

For MSPGCC support can be inferred by features present in the headers; for
Code Composer Studio this is not true for the 2xx family where there are no
macros that identify availability of PxSEL2.
close #75: add API for port SEL control

Macros for HPL and HAL configuration of peripheral functions across all
families.  Unit test validation on 2xx, 5xx, and FR5xx families.  Note that
47xx devices are not supported for secondary/tertiary functions at this
time.

Also correct offset of SELC registers in HPL structures per TI change in
upstream msp43mcu 25.09.2012.
pulsecap example: fix missing activation
Update for supposedly stable enhancements