This is a modified version of the default keymap for Gergo with some changes.

## Changes:
 - Rehaul thumb keys. For my hand size, the L and R thumbs rest on space and backspace, and one finger outward, are tab and enter.
 - = has its own dedicated key to facilitate typing "<space>=<space>", which is a very common trigram in programming.
 - Change navigation into a T-shaped cluster and add Home and End keys. T-shaped, because it's similar to arrow key cluster and most keys are on the home row, while sharing the number layer.
 - Separated mouse navigation into a separate layer (in favor of T-shaped arrows, which require 2 rows).
 - Difficult-to-reach key positions are mostly unused.
