Roll all drag modes into one mode for brush resizing.
Remove TrenchBroom.sln.cache from Windows project.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Add documentation about line number selection.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
- Reset modifier keys when app is activated / deactivated.
- Fix hint brush filtering.
- Update documentation.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>