Update README.md (#395)
Update README.md (#395)

*Added logo of sensenet Community website to the README.md file 
*Re-Formatted the text (intro text)
*Added Contact information section & Social Media Links (this helps people to follow social media pages of sensenet)
SenseNet/sensenet.github.io,SenseNet/sensenet.github.io,SenseNet/sensenet.github.io