Update Readme.md

[obitodarky]

Is your feature request related to a problem? Please describe.
Currently, Readme.MD does not seem to be updated and looks very confusing for new contributors as there are a lot of things that seem to be missing.

Describe the solution you'd like
The Readme.MD should be updated with the following points to be kept in mind:

• Describe Xcode and Swift versions used in the project
• Have a table of contents
• Have a getting started basic guideline (Guides on Xcode, CocoaPods and project installation and how to test them)
• Have a different file for Contributing.MD and reference it in Readme.MD

[obitodarky]

@benhalpern I would like to work on this issue!

[jessleenyc]

@obitodarky go for it!