Merge pull request #4 from blackvladimir/master

Error messages
SUBTRACT does not have to return object
Bugfix
Bugfix
Bugfix
Bugfix
DIFF is binary
Bugfix
Bugfix
Bugfix
New DIFF command
SUBTRACT and DIFF commands
Bugfix
ORANGE
Merge pull request #5 from blackvladimir/master

fix rotation of object list
ROTATE
Testing commit
Commenting out some error messages
Bugfix
COLOR with only one argument