Support labels without trailing ':'

[watmough]

I have to say that I really enjoy working in 6502js. It's a useful and fun piece of software that's really helped me generate some actual working 6502 code for the first time since being a teen in the 80's.
There's at least one thing that might help to make it even better.
In 6502js, labels require a trailing ':'. This makes it harder than need be when working in both 6502js and other 6502 assemblers such as 8bitworkshop.
I'd be happy to take a look at making this change in the js.

[BigEd]

Hi! By all means take a fork and see if you can get this working. It seems to me that the input is a bit more ambiguous and parsing might be less reliable. First thing to check is that it works for all the easy6502 examples.

[AverseABFun]

Sorry, but that it how basically all assembly I have ever seen functions(also I know this thread is like 7 years old) and it makes sense to keep it the same here.