Again replace "git-windows-sdk" with the shorter "git-win-sdk"

Hopefully this is the last time ...

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
installer: Replace "mingw" with "SDK" also in the large wizard logo

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
installer: Ensure to start up in the installation directory

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
installer: Allow to use spaces in the application name

This applies only to places where the application name is displayed. The
installation directory name still gets spaces replaced with dashes.

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>