Created "DragBox"

git-svn-id: svn://esoteric.clanlib.org/public/ClanLib/Development/ClanLib-3.0@10067 cc39f7f4-b520-0410-a30f-b56705a9c917
- Initialized all variables in Slider_Impl

git-svn-id: svn://esoteric.clanlib.org/public/ClanLib/Development/ClanLib-3.0@10068 cc39f7f4-b520-0410-a30f-b56705a9c917
Update gitignore file
Fix a small error in x11_window/input_device_provider_linuxjoystick.cpp
Merge branch 'master' of https://github.com/Zenol/clanLib-3