Also updates a lot of other things (brush size now independent from
scale factor, split some files, and a lot other things; removed erase
safeguard as now erase is supported by undo/redo; tried adding github
prettier autoformatting to pull requests;
may have some other things as well
Signed-off-by: Victor Seiji Hariki <victorseijih@gmail.com>
Former-commit-id: 0ba21f23c69f9dca2c3189a838b945900b01f81d
