Make the build work with Cocoapods [FOR DISCUSSION]

This update detects if CWD is a Workspace and if so it will try the build the project. This works with my CocoaPods project. It is ugly, hacky, and I have no idea why/how it works. Fixes #26

**Requesting review of this code:** Does it work with your project in the below intended use case? Are you able to simplify the build code used?

INTENDED USAGE:

````
git clone YOURPROJECT myproj
cd myproj
pod
git clone https://github.com/jonathanpenn/ui-screen-shooter.git
vim ./shoot_the_screens.js
ui-screen-shooter/ui-screen-shooter.sh
# Start drinking beer
````

See also
  * https://stackoverflow.com/questions/22663294/xcodebuild-fails-when-run-from-jenkins-works-in-terminal
  * https://stackoverflow.com/questions/21602965/cocoapods-command-line-build-fails