Fix running box.exe from c:\ root folder on Windows causing invalid Java arguments being printed to screen.
Skip installation of packages if they are already installed unless user provides --force option.
When running box install, ensure that the box.json file exists. If not, display friendly message.
Merge pull request #14 from gcopley/master

https://ortussolutions.atlassian.net/browse/COMMANDBOX-87 #resolve #close
https://ortussolutions.atlassian.net/browse/COMMANDBOX-86 #resolve #close
https://ortussolutions.atlassian.net/browse/COMMANDBOX-90 #resolve #close