Added Thumbs.db to .gitignore

(cherry picked from commit 503497298026930001715c0811e243506e1e3ae3)
Added visual studio gitignores

(cherry picked from commit 68337ac8351800c2fe36eb16e32790b473167b76)
Replaced banner image on about page.
Bumped version numbers for 1.1.2
Added checkpoints for 1.1.2
Actually added diffshield to makefile.linux-mingw

(cherry picked from commit daafff74662d18f1580125d19061c2a9641eba41)