gdi32: Optimise StretchBlt for the case where no stretching is being done and the whole image is being set.

In this case, we can just call SetDIBits which is likely to be a lot faster.

coreaudio: Set mDataByteSize of the buffer to the amount data provided. Greatly helps reduce audio corruption on buffer underflows.

RegEnumKeyExW takes a character count for the key name, not a byte count.

This reverts commit 6886a49c.

RegQueryValueExW takes a byte count, not a character count (spotted by 
Detlef Riekenberg).

dplayx: Fix incorrect check in DirectPlayLobbyAImpl_EnumLocalApplications and IDirectPlayLobbyAImpl_EnumAddressTypes.

Dereferencing a function pointer and checking it against NULL doesn't 
make any sense, so remove the checks.

Dereferencing a function pointer and checking it against NULL doesn't 
make any sense, so remove the check.

Some files use wine/exception.h without also including excpt.h, but 
excpt.h is needed when using native exception handling.

Instead only clear the number of bytes requested and mark the remainder 
as uninitialised.

ntdll: Fix the use of oldSize in RtlReAllocateHeap as both the size of the old block and the number of bytes used in the old block.