Implement canvas deletion
Implement canvas creation
Implement canvas saving
Merge remote-tracking branch 'upstream/master'
Fix CanvasManager by forcing it to evaluate the numeric values as float.
Prior to this commit the maximum digits after the point were reached to quickly.
Merge pull request #22 from baerenfaenger/master

Implement canvas deletion, creation and project saving (which includes saving canvases)
Merge pull request #26 from boom1992/master

Add implementation for being able to edit project properties, User Story #14
Merge two methods who did the same (update project meta data)