.bashrc: Add common commands to HISTIGNORE

Signed-off-by: Alan Orth <alan.orth@gmail.com>
.bashrc: ignorespace -> ignoreboth

ignoreboth will ignore commands starting with space as well as dup-
licate commands.

Signed-off-by: Alan Orth <alan.orth@gmail.com>
.bashrc: Re-enable history saving

Signed-off-by: Alan Orth <alan.orth@gmail.com>