With assistance from H. Verbeet.

caching the ID of the string to load before overwriting it with an
Alloc call.

Get rid of the no longer needed 16->32W mapping functions.

Get rid of the no longer needed 32W->16 mapping functions.

Make the column resizing smooth in full drag mode even for listview
with lots of elements by redrawing only the resized column and calling
UpdateWindow.

- create an abstract interface for contexts, and use it for certificates
- create a simple context list, and use it for memory stores

rpcrt4: Fix some comments and move the NdrSimpleType* functions out from amongst the NdrSimpleStruct* ones.

The IStorage (DocFile) implementation was adding empty blocks at the
end of the file every time a caller wrote data that was not a multiple
of 512 bytes.  If the caller made a lot of very small writes the file
size could be huge even though the data in the file was tiny. This was
caused by BlockChainStream_SetSize trying to allocate file blocks for
the new data using a condition that bore no relationship to the
required condition, and it was not necessary to do so at that time
since it is done (the right way) by StorageImpl_GetNextFreeBigBlock
(called via BlockChainStream_Enlarge).

Windows doesn't like when a thread plays games with the focus, that
leads to all kinds of misbehaviours and failures to activate a
window. So, better don't generate a mouse click message in
mouse_ll_global_thread_proc.

Implement some basic opengl accelerated blts from and to render
targets. It's not perfect yet, but enought to make some D3D apps
happy. For now the only supported operations are:

- Full screen back -> Front buffer: Just call present
- Offscreen surface -> render target
- Render target -> offscreen surface(slow)
- render target colorfill