Modifications for Windows compatibility

[marcochiesi]

This pull request includes the following changes:

• All exec calls have been rewritten using an internal function that executes commands synchronously using execSync
• All the cd commands have been rewritten using the cwd option
• The awk command is replaced by gawk on Windows platforms (still using awk elsewhere)
• The svn add/remove commands have been rewritten in order to avoid the usage of grep, and adding the --no-run-if-empty parameter to xargs. I.e. svn status | grep -v '^.[ \t]*\\..*' | grep '^?' | awk '{print $2}' | xargs svn add became svn status | gawk '/^[?]/{print $2}' | xargs --no-run-if-empty svn add

These modifications have been tested on a Win7 machine, with svn and Git command line tools, which include the gawk command natively (no need to install it explicitely). Git command line tools are provided both by the official Github client and by the Atlassian Sourcetree client.

Everything should be still running fine on *nix platforms, but it would be better to take some more tests.

As for the SVN server-side it has been tested on official WordPress SVN repo and also on a private SVN repo on Assembla.com.

Note: this should fix issues #14 and #2

[stephenharris]

Thanks @marcochiesi , I'll be testing this later this week and will then make a release.

[stephenharris]

@marcochiesi Sorry, I never did get to testing and releasing your changes. I'm currently re-factoring the plug-in, and have included most of your changes, so I'm going to close this.

Thanks again for the PR.

[stephenharris]

I had to revert the change using --no-run-if-empty as this is not supported on OSX.