Added posibility to configure Restangular fields

fixes #12
All changed made
Merge pull request #14 from mgonto/12-custom-param-names

Added posibility to configure Restangular fields
Changed README

First showing usage, then showing configuration now that configuration is getting bigger.
Update CHANGELOG.md
Update README.md
Remove useless commas
Add some tests
Add more HTTP methods
Add Karma as part of the build process