KfW auto-complete support

Use the registry to store and retrieve principals for auto-complete.
Remember principals from successful autentications.
TODO: combine realm/username in principal; 'remember principal' checkbox;
reset button; add to support 'change password' dialog as well.

Signed-off-by: Kevin Wasserman <kevin.wasserman@painless-security.com>

[kaduk@mit.edu: style cleanup, copyright/license on new file.]

https://github.com/krb5/krb5/commit/6201bbc23f1c307e6278af72eaa8e93dc898fedf
Author: Kevin Wasserman <kevin.wasserman@painless-security.com>
Committer: Ben Kaduk <kaduk@mit.edu>
Commit: 6201bbc23f1c307e6278af72eaa8e93dc898fedf
Branch: master
 src/windows/leashdll/Makefile.in |    1 +
 src/windows/leashdll/lsh_pwd.c   |   13 +
 src/windows/leashdll/lshutil.cpp |  586 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 600 insertions(+), 0 deletions(-)