Clean up the help output a small bit

Still kinda messy, but this may help with auto-generating
man pages and other documentation just a bit...
Additional cleanup to interactive help
bladeRF-cli: Fix mixed-up between --version and --lib-version

--version was reporting the libbladeRF version, while
--lib-version was reporting the bladeRF-cli version.
bladeRF-cli: Fixed incorrect write size (rx, binary SC16Q12)
libbladeRF: Removed prototype for removed function.
bladeRF-cli: Improved script support, quoted param support, misc. cleanup

Scripts can be invoked from within other scripts, using the "run"
command. An error is reported if a recursive loop is detected.

An "echo" command has been added for debug purposes.

Parameters may now be surrounded in double quotes to include spaces.

Removed extraneous error messages from main(); The preceding functions
print error messages if needed.

Removed error-out if no device is attached. This allows scripts to be
run if the device is not attached. Commands already verify that a device
is attached, if required.
bladeRF-cli: Added rx/tx "wait" command with optional timeout

"rx wait" and "tx wait" may be used in conjunction with scripts to wait
a specified amount of time before exiting, or to wait until the
configured number of samples are received/transmitted before exiting.
bladeRF-cli: Version bump for script support and quoted params
bladeRF-cli: Wait for transition from INIT to IDLE in rxtx_startup()

This fixes issue #171, as we ensure we start up before attempting
to issue shutdown requests.
Initializing uninitialized variable.
bladeRF-cli: Merged rtucker's 'fix_bladerf_cli_help_consistency' branch
bladeRF-cli: Additional help text cleanup
Use help2man to generate man pages (fixes #165)

A little more lightweight than the doxygen approach,
and keeps the documentation harmonized with --help.

h/t to A. Maitland Bottoms for pointing me to this.
libbladeRF: Corrected documentation commands in README.md
bladeRF-cli: Added a clock_gettime() implementation for OSX
Merge branch 'dev-issue165-use-help2man-rev3' from https://github.com/rtucker/bladeRF
host: Added option to disable "warnings as errors" in builds

Developers should always build with -Werror or /WX. However, we've had a
few cases with different compiler versions throwing errors that devs
didn't see, breaking master for users. The intention of this change is
to give those users a quick workaround, rather than requiring them to
hack around the warning in the source.
host: Updated README.md to include CMake TREAT_WARNINGS_AS_ERRORS option
Adding time.h for timespec.
Fixing time getting for OSX.