finding xcode 6b4 tracetemplate

## motivation

Correctly locates the Automation.tracetemplate for Xcode 6b4.

## needs review

There are several changes that need approval.

- [ ] drops support for Xcode < 5.0
- [ ] asks instruments for the path to Automation.tracetemplate; no more hard-coded paths - https://github.com/jmoody/run_loop/commit/156571302dadeb33a2f3a905cab3cad5e70f6051
- [ ] bumps version to 1.0.0.pre1 - see https://github.com/jmoody/run_loop/commit/3146802ced901dc1f9a58e33f53a852e1091619c

cc @krukow