Cause MenuDeactivate event to be delivered when appropriate

This is achieved by moving the FireMenuDeactivate call to
MenuStrip.Dismiss and causing it to be called in a couple of places
where it ought to be.
X11: improve handling of WS_EX_TOPMOST

Currently, WS_EX_TOPMOST is handled by making the window transient-for
the root window.  I was unable to find any documentation that indicated
that this would have the desired effect.  Instead, use SetTopmost to
set _NET_WM_STATE to _NET_WM_STATE_ABOVE, per EWMH.

Also, use XMapRaised to raise topmost windows to the top of the stack
when mapped, as a last ditch effort to support window managers that
do not respect _NET_WM_STATE, such as xmonad.

This fixes an issue I encountered when running a winforms application
in xmonad, whereby drop down menus would fail to re-open if windows
had been re-arranged after the menu was first opened (in reality,
the menu was hiding behind the form).
Ignore the gdiplus dllmap on Windows.
Fix Bug 4811, xbuild should find xml documentation
[System] Don't overwrite custom Connection header on HttpWebRequest
[System] Add crude (for now) socket stealing of an HttpWebRequest.

HttpWebRequest is a very tricky piece of code when it comes to its socket, this patch is more like a hack to get something working out of it but it's definitely not the best option.
[System] Implement a first pass of ClientWebSocket.
[Scripts] Fix a Shebang in mono-test-install for freeBSD
Fixed inconsistency in XmlSchemaValidatingReader between Mono and MS.NET
Remove text from article
Remove comment, refer to the spec instead
Use __builtin_popcount () in mono_bitset_count ().
Bump ikvm
Reduce/remove the probability of having test failures wrt UdpClient.Available
Bump ikvm. Fixes the build
[bcl] Fix BlockingCollection.TakeFromAny to handle when no items are available on the first collection. Fixes #6095.
Add workaround for DNS garbage return
Simplify locale fetching, we have very simple needs
Move undef HAVE_SIOCGIFCONF later so it's not defined again by other includes
Unify Array/List FindIndex/FindLastIndex handling and argument checking. Fixes #14632