bug fixes and new features in soligen2010 fork

[soligen2010]

I like the base functionality of this library, so I addressed some of issues in my own fork, and added some features. I think my fork is now working very well and solved some quirkiness i noticed. Please test out my fork here: https://github.com/soligen2010/encoder

Since there has been no pull requests into this library for 2 years, I don't know if my pull request will be merged or not - hopefully it will be.

Here are some highlights. Please see my commit list for more details.

Disabling double click now works properly
Ability to enable/disable the hold/release button feature
Fixes to the table based algorithm used when ENC_FLAKY is set. Encoder now decrements properly
Support for ESP8266 (see example)
2 encoders or buttons can be used at the same time (see example)
Can disable the encoder so an instance can be used with just a button (see example)