Remove customizations for smartparens lighter.
Change default theme.
Change default key binding for `er/expand-region`.

Previous binding was overriding default binding for `mark-word`, which
can be handy sometimes.
Add command for unfilling paragraphs.

Adapted from:
https://github.com/mwfogleman/config/blob/master/home/.emacs.d/michael.org#unfill-paragraph
Add command for finding file as root (with Ido completion).

Adapted from:
https://github.com/mwfogleman/config/blob/master/home/.emacs.d/michael.org#unfill-paragraph