First part of this change was proposed by Byeong-Sik Jeon.
Additionally respect parameters give to us by ImmSetCompositionWindow
for placement of the composition window.

Remove unneeded checks on the GetModuleHandle() return value for cases where we are linked with the dll.

rpcrt4: Fixing the using of the auth_len values the wrong way round - PKT_PRIVACY implies the packet will be encrypted, not just signed.