Add test functionality

[Igorjan94]

Adds test to current set of tests (problem must be specified)
acedit --add-test -p A -c 847
<input here>
^D
<output here>
^D

[Igorjan94]

Hmmmm...
I thought there will be two PR..

[coderick14]

Hey. Your code looks great. There are a few minor changes that need to be done. But I'll take care of it. Can you just send the last two commits ( 2478c1d and ae55deb ) in a different PR?

You can send the initial PR from your branch some-more-languages-and-compiler. Once it's merged, you can give a PR for remaining two commits.

Thanks a lot!!

[Igorjan94]

PR'd my branch.

It'll be great, if you'll add "change test by number" functionality.

Also I had some problem with installing it from source with python3:

...
File "ACedIt/acedit/install_entry.py", line 13, in run
    from main import supported_sites
ModuleNotFoundError: No module named 'main'

I've also noticed, that 2to3 option is added only to extra dict, though adding it to setup options doesn't resolve this problem..