use bitset when locking, avoid manual index & mask calculation
update check() to use boolean logic instead of returning int status
remove wip address-range, just use the {begin, end} pair
uint8_t instead of unsigned char when dealing with data

Clean-up the sensor code to have intermediate 'raw' representation of
every value read from the sensor.

Update energy code to include 'actual' value that can be read directly
from the chip. Adjust the 'expected' value that we were already calculating.

Move settings & build flags into local namespace
Fix various functions referring to settings, when i2c is initialized once
Correctly use feature-flags in the .cpp instead of the .h

- general conversion from .ino modules into a separate .cpp files
- clean-up internal headers, place libraries into .h. guard .cpp with _SUPPORT flags 
- fix some instances of shared variables instead of public methods
- tweak build system to still build a single source file via os environment variable ESPURNA_BUILD_SINGLE_SOURCE

* Config: remove prototypes.h

* fixup order

* word

* add missing

* fix warning while still using .ino

* bad at c/p;