Initial ReadyTalk helper, git autocomplete, bootstrap iTerm2 install, small ssh-agent tweak

This is my initial attempt at a helper for the ReadyTalk deploy script. It should walk you through the setup but, basically, you need to have

```bash
export RTWD=<pathToBaseRTCheckout>
export RTPOND=<configurationPond>
```

in your ~/.localrc file. You can also use the convenience methods `set-pond` and `set-rtwd` to set these variables up for you (or change them on the fly). 

Then you can use
```bash
deploy <command0>...<commandN>
```
to quickly deploy code from your working directory. 

The helper function is also great for aliases, so you can edit your `aliases.sh` file to have helper aliases like
```bash
alias deploy-mac='deploy deploy-client-mac'
```
to make your life easier.

This pull request also contains a small change to only run the `ssh-agent-setup.sh` on Linux. OS X will automatically unlock your keychain and start an ssh-agent when needed.