new .gitignore to ignore generated files

Newly created .gitignore so that generated files from Visual Studio are
ignored.
updated .gitignore

Added additional obj and bin directories.
Merge pull request #1 from BruTile/master

Update from origin
Merge pull request #2 from BruTile/master

Merge updates from origin
Merge pull request #6 from josh-cooley/master

.gitignore to ignore generated files