Clean up vimrc

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>
vimrc: mappings, set undofile

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>
zshrc: ttytter path, openbox --reconfigure

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>