added low battery detection test program; based off of functional
Merge branch 'master' of https://github.com/dhiltonp/hexbright
removed an extra int i
low voltage detection no longer requires calibration, and is accessible through BOOL low_voltage_state
Merge branch 'master' of https://github.com/dhiltonp/hexbright
a small tweak for up_n_down that might help the problem of missing really fast clicks
get rid of an unnecessary float cast
convert update_delay to microseconds
Revert "convert update_delay to microseconds"

This reverts commit 3a15f0bc7a9926f3b976f3f9968f3a14324a91f5.
low battery detection code is now 8 bytes smaller
Merge branch 'master' of https://github.com/dhiltonp/hexbright
reduce the compiled size of up_n_down by 442 bytes
updated up_n_down, new tactical light blinky mode and other tweaks