Vaadin7: .gitignore, version-properties, SNAPSHOT release

Hi Tomi,

I started to work on your vaadin7 branch. First thing I had to was adding a .gitignore file, please include this in the branch, so every developer can profit from one common file.

2nd, I added version-properties for the vaadin deps and updated them to the latest versions (7.05). 

3rd, I set the version to 2.2.0-SNAPSHOT. Since I clean/install a lot during development, the SNAPSHOT flag eases separation of build/intergration artifacts and released artifacts.

regards
Jan

ps: thanks for finally mavenizing this great project!