API Support for Beaglebone Blue Week-4

Hi all!

This is the following I’ve accomplished in this week:

  1. Finished the APIs for ADC and PWM by making some modifications and removing the mmap functionalities.

  2. Split the APIs into individual APIs to improve readability.

  3. I am almost done with the IMU and Pressure sensor APIs and will be done by tomorrow

  4. Wrote the documentation for the APIs in the readme.md file in my github repo.

  5. Updated the wiki pages in the repo.

  6. Finished the mid-term evaluation. :stuck_out_tongue: