Use attr_reader for cols and rows in Canvas
Canvas now checks if co-ordinates are in bounds when you try to set a pixel
Picasso::App no longer uses canvas#in_bounds? because canvas does this itself
Removed eftover paramater handling from before parse_params
Adds a colour object
Fixes syntax error
Fixes syntax error
Learned how to spell initialize, more \'i\'s
Removes is_valid_colour? and uses new Colour class
Colour raises an exception if an invalid colour is entered
Sublime Text has corrected all my white space. Also, Fixed an end expected else found error majig