Add BOXEN_SRC_DIR environment variable to config
Fix homedir test with env var. Fix homedir tests when boxen is installed.
Format all strings according to Github coding style guide
Merge pull request #51 from mmuehlberger/master

Add BOXEN_SRC_DIR env variable as possible configuration
Disable KeyChain errors on missing items, support OSX versions gt 10.6.
Wrap REPORT_KEYCHAIN_ERROR macro in do-while block, add semi-colons to macro usage.
Build new boxen keychain helper bin