`set_simulator_device` is now a shell script.

For increased reliability.
Provide for `subliminal-test` to use the Xcode 4.6 toolchain
while 5 support is pending. (fixes #33, refs #32)

This entails setting the Xcode directory to that of Xcode 4.6 before launching
`subliminal-test`, as described in the documentation, as well as forcing the CI scripts
to open the Simulator corresponding to the currently selected dev toolchain: the
Xcode directory in-and-of-itself has no effect on which "iPhone Simulator" is launched.
`subliminal-test` now properly builds a workspace if one is specified. (fixes #31)
`reset_simulator` is now a shell script.

For increased reliability.
Allow a second more for the Simulator to start up as required by the CI scripts.

To ensure that it is fully open before the next action occurs, particularly instruments launching.
Merge pull request #34 from inkling/jeff/respect_workspace_arg

`subliminal-test` can now be run alongside the Xcode 5 toolchain, and respects the "workspace" argument.