added payload to execution
    * execution now contains payload for sending a body in POST/PUT calls
    * renamed data from execution to formData
apiCall now takes data and type, and switches between payload and formData
Merge remote-tracking branch 'origin/executionPayload' into executionPayload
Added rest call overview page
* adding rest call overview to have an overview about all available rest calls
* refactored $scope.api to $scope.restCalls
* adapted tests for new parameter "type"
* added type to rest call UI
Merge pull request #23 from TheBay0r/restCallOverview

Rest call overview
Stabalized call selection
 - updated angular-material to version 0.6.1