PicoC supports two target modes (check SConstuct) -
regular floating point PicoC and NO_FP.

timer_data_type for PicoC does not depend on the
PicoC target - i.e FP/NO_FP.
PicoC support for timer module.

Added support for PicoC in the timer module.
Now, the PicoC and Lua parts of the timer
module coexist in src/modules/tmr.c
Fix compiler warnings in iv.c