Subtle change: Added a space in front of the command that's run in the
new tab. If you use `export HISTIGNORE=' *'` in your shell, this will
ensure that commands starting with a space will not be included in the
history. Since the command sent to the new tab by the `tab` command
probably shouldn't show up in the history, I added a leading space
character.
Merge pull request #250 from nwinkler/osx-tab

Open new OS X tab change: Ignore command in history