Support for windows platform

As you askes me, here's my version working on windows.
I was a little surprised by the develop branch having a totally different structure from master where I originally changed the code.
I have 2 points I'd want you to see:
- Try ```dbDump```. I don't know if it still works on Linux without backslashes in cmd
- I don't know what to return in ```dbReplace()``` as there's no more cmd to return. Now I use shelljs sed command... so I thought you could return shell but I don't know what to do with unit testing.

I hope my contribution is useful and usable for you (and others).

However, thank you for this fantastic grunt plugin!