Update Color's #to_s, #inspect
Change default #inspect format

Was: (Shoes::ClassName <0x01234567>)
Now: (Shoes::ClassName:0x01234567)

Now, by default, Shoes objects inspect like normal Ruby objects, only
with the parentheses from Shoes 3, instead of angle brackets. This
change makes sense since we are now using '::' to delimit namespaces.