Inconsistent and unconventional style

[langston-barrett]

There are some aspects of souffle-mode that have an unconventional style and should be unified. For instance, from the Emacs manual:

Don’t make a habit of putting close-parentheses on lines by themselves; Lisp programmers find this disconcerting.

There are lots of parentheses on their own line in souffle-mode.

Indent the file using the default indentation parameters.

This is an indentation of 2, not 4. souffle-mode is inconsistent on this front, and that's my fault (I introduced some code with the standard 2-space indentation). Since this is my fault, I volunteer to fix it after I get a few more features in.