.screenrc: Add a .screenrc for sanity
.gitconfig: Add some guitools
bin/share_file: Script to share files on kasumi

This of course only works by default for me, but could be adaptable
for other servers. Uploads files via rsync+ssh, gets public links to them.

Add a kasumi_clean alias to kasumi that doesn't forward ports, makes the
rsync output less noisy.
.zsh/rc/cygwin.sh: Use ST3 instead of ST2, add proc_retry:2
Update submodules