don't crash if ~/Library/Logs/DiagnosticReports does not exist.

This was pretty bad - xctool would actually crash if this directory
didn't exist (meaning you had no crash reports on your system).

Fixes issue #11

Tested with...

```
./xctool.sh -workspace
xctool/xctool-tests/TestData/TestWorkspace-Library/TestWorkspace-Library.xcworkspace
-scheme TestProject-Library -configuration Debug -arch i386 -sdk
iphonesimulator test -only TestProject-LibraryTests
```
Merge pull request #14 from facebook/fpotter/dont-crash-when-there-are-no-crash-reports

don't crash if ~/Library/Logs/DiagnosticReports does not exist.
adding TOC in README
adding some notes about the Facebook CLA in README
make tests pass now that TestProject-Library has disabled tests.

In e071d39849, a new test class got added to the scheme but it's
disabled.  So, we'd expect the SenTest args to change.
let's call it v0.1.0 and you can print the version with -version

Homebrew requires versioning (see issue #8)
Add an archive action
Fix detection of when a build is needed with better git fu
if a target name included spaces, we'd crash when running tests.

This fixes part of issue #19.  The target name was "Mantle Mac Tests",
but internally we thought the target name was "\"Mantle Mac Tests\"".
xcodebuild's -showBuildSettings will quote target names with spaces and
we need to account for that.
sometimes 'run-tests' would fail with OS X logic tests.

otest-shim watches for the SenTestingKit framework to get loaded before
it does its swizzling.  In this case, the framework path we were
watching for was overly specific.

We were waiting for...
  '.../SenTestingKit.framework/SenTestingKit'
But, the image path was...
  '.../SenTestingKit.framework/Versions/A/SenTestingKit'

... and so we were never swizzling.

This is part of a fix for issue #19.
Start of a JUnit reporter

Conflicts:
	xctool/xctool.xcodeproj/project.pbxproj

Conflicts:
	xctool/xctool.xcodeproj/project.pbxproj
Output it all in one file