Update to new powerline-fontpatcher

The font patcher inside the main Powerline repository was removed
Patch Powerline font patcher for Ricty glyph size

The Powerline font patcher normally scales the Powerline glyphs to match
the largest width and height of any glyph in the Latin-1 extended or
box-drawing ranges. This is far too big for Ricty, so this patch
overrides the font patcher with a custom glyph bounding box
(0, -525, 1025, 1650) that works well with Ricty.