* [firmware][ARM] Adjust some value limits for mix sources and update editing UI for LSs, CFs, & telem. bars:
* Increase timer limits to +/-8:59:59 when used with LSs, CFs, & bars;
* Increase Lua script output limits to +/-30K;
* Trim limits based on extended limit model setting;
* Limit TX voltage to 25.5;
* Limit TX time comparison value to 29:59m;
* Use proper GVar limits (user-configured), display precision, & unit in LSs & telem. bars;
* Display timer values properly with hours (instead of mmm:ss).
* [firmware] getTimerString() would fail with times >= 100min if hours weren't shown.
* Fix builds w/out GVars.
