Add depends to library.properties.
Fix compiler warnings in example sketches.
Example sketch bug fix.
Rearrange #includes.
Update keywords.txt file.
Change to use TimeLib.h.
Improved support for non-AVR architectures.
Change license to GNU GPL 3.0.
Move defines not needed in .h file to .cpp file.
Update examples.
Cosmetic and style changes.
Add GNU GPL 3.0 LICENSE.md file.
Add CONTRIBUTING.md file.