Currently, the registry path and registry key is hard-coded to `Software\\GnuPG` with key `Install Directory` in libkleo. For VSD/GPD this needs to be customizable.
for 64 bit VSD: `Software\\GnuPG:VSD Install Directory`
for 64 bit: `Software\\GnuPG:Install Directory`
for other (i.e. 32bit): `Software\\Gpg4win:Install Directory`