added python compile command

[cpaulik]

This makes using compile mode in python easier by doing the following:

• automatically changes compile command to
  python (buffer-file-name
  for python buffers
• automatically starts comint mode in python mode to allow interaction
  with debugger

Fixes #805

[syl20bnr]

Excellent ! 👍

I reworked it like this:

• since I removed the advice the key binding is major specific SPC m c c
• without a universal argument it does not ask for a command, with an universal argument it asks for a command (SPC u SPC m c c)
• I added SPC m c C to compile and then switch to the comint buffer in insert state.

Commit: 3098a1a

Thank you!
Cherry-picked in develop, you can safely delete your branch.

[syl20bnr]

oh you got the 400th PR congratulation ! :-)

[cpaulik]

Thanks for making functions out of it, way cleaner.

I tested it and found a problem when the compile-command is already set to e..g a first python file and you want to execute a second python file. I also moved point to the end of Buffer if we are switching to the comint buffer, so we can directly interact with the debugger. see PR #824

Yay 400th 😄