Allow proper formatting in aliases.fish

Modified the `ag` function to return function blocks so that now
aliases.fish can be stored with proper formatting rather than as single
lines for each file.

Note: For this to work, functions must begin without indentation and be
closed by the `end` keyword on a line without indentation.

Further note: Unfortunately, this also slows down runtime for ag. :(

Nother note: fish_indent (or maybe pygmentize?) improperly indents lines
where begin ... end blocks are used.
Some formatting and cleanup
More formatting tweaks
Various changes & addit'n of math & list functions
Add pointless alphabet ranging and other things
Add filter