#91 - Ability to disable doubleclick to dock

A new property was added to the FloatWindow, DoubleClickTitleBarToDock,
to allow disabling the behavior of redocking a float window when double
clicking the title bar.  Also converted WndProc to a switch statement
for better readability and negligible performance.
#82 - Fix docking indicators in TopMost case

The article referenced by DragForm specifically mentions the need to
make it TopMost, but a note in the comments of DragForm said it wasn't
necessary. It is necessary.
Normalize line endings

No functional changes included in this checkin, this is simply to
normalize the line endings so that git diffs are useful again. This
appears to be a relatively new change from github requiring the addition
of the .gitattributes file.
#78 - Fix ObjectDisposedException in sample

When loading from XML the explicitly referenced controls were not being
recreated (like the toolbox, etc; where there is a private member
holding a reference to the form).  Solution is to recreate these forms
before attempting to load from XML, just as load from code is doing.
#69 - Restore support for multiple UI threads

Make the local windows hook unique per thread, to ensure a hook is
installed for each UI thread in the application using the DockPanel.
Remove unnecessary locks

There is no reason to use a monitor or any other thread synchronization
mechanism in this library.  WinForms are inheriently single-threaded and
the dockpanel can only ever be accessed from the thread on which it was
created.
moved to v4.5
FloatWindow sizing and positioning sizes