* Do not reload bitmps during theme update, unless reload argument is true
Trying to optimize speed for theme color changes.
FlySky is not optimized yet.
* Do not update theme from Lua lcd.setColor(CUSTOM_COLOR, x)
Some widgets like e.g. Timer2 constantly change CUSTOM_COLOR, and this seems to slow down things
* Lua function lcd.setColor() only updates if color is changed
To avoid that scripts calling lcd.setColor() repeatedly trash performance
