[PATCH 2/4] oleaut32: Implement decoding of SLTG help strings.

[Vijay Kiran Kamuju]

Tested using builtin oleview and ole1 typelib from older DDks.
oleview now shows the helpstrings for SLTG interfaces and coclasses.

From: Dmitry Timoshkov 
Signed-off-by: Vijay Kiran Kamuju