Merge pull request #17 from sarvsav/develop

Updated presentation details and assigned tasks
added my name as author
Merge branch 'authorAdd' into develop
Merge pull request #18 from RaoulJWZ/develop

Authoradd
Merge pull request #19 from sarvsav/develop

Added Comments for phsyics.cpp
Merge pull request #20 from sarvsav/develop

Added instruction to install SDL and other libraries
Update README.md
Added entity class and its features