execute_sync added
added check for custom commands so that we can use the constructor format
changing test to function. cleaner that way.
properly assign context for Constructor style custom commands
--version
small fix to capabilities for loop
added constructor style support for custom commands based on PR #48
Merge branch 'master' of github.com:turigabor/nightwatch into turigabor-master

* 'master' of github.com:turigabor/nightwatch:
  --version
moved the alias -v to --version instead of --verbose as it is more commonly used in this sense
updated quotes for consistency and fixed some issues with syntax
refactored execute_async and execute to share the common logic and improved the test coverage
0.3.4