Update README.md

Add how to acces web frontent from devopment machine
Update README.md

Improve description
Update README.md

fix bad headline
Update README.md

Fix typos
Update README.md

Another small update of the documentation
Update README.md

There was still a typo. And another small rephrase.
Merge pull request #94 from kDot/master

Describe how to access web frontent of syncthing backend while development