More readme changes

No standard template to file bug in README. So listing them.

1. Can we include a link to the license file?
2. "note: shakti-sdk is tested in ubuntu 16.04 only." Make this note bold.
3. Change "Please open the terminal and try the below commands. This repository can be cloned by running the following commands:" to Please open the terminal and run the following commands to clone the repository: 4.Please put the above two lines in .bashrc file in home folder. See image below for reference. The image should be immediately below this line or remove the line "See image below for reference."