in float build, uV and sign are included in mV
in int build, uV and mV are absolute, sign is -1, 0, 1
added rounding of uV values
added optional test function
* ads1015 is supported, up to 4 devices can be connected at the same time
* removed debug, updated documentation
* changed to oop API
* added __gc to handle active timer cleanup
* reworked argument validation and error reporting
* stack is no longer messed up after __del
Pawel Jasinski
fetchbot