zsh: try case-insensitive completion if simple completion generates no matches

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
zsh: set custom prompt

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
tmux: add basic tmux config

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
tmux: enable mouse mode

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
tmux: set starting index for windows and panes to '1'

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>