Phase 1 of RETS 1.8 implementation

git-svn-id: https://code.crt.realtors.org/svn/librets/librets/trunk@1560 fe7ac059-47f5-0310-8599-d0339b4e125c
Phase 2 of RETS 1.8 implementation

git-svn-id: https://code.crt.realtors.org/svn/librets/librets/trunk@1561 fe7ac059-47f5-0310-8599-d0339b4e125c
Update Search for RETS 1.8 and to parse an XML payload

git-svn-id: https://code.crt.realtors.org/svn/librets/librets/trunk@1562 fe7ac059-47f5-0310-8599-d0339b4e125c
Fix const correctness

git-svn-id: https://code.crt.realtors.org/svn/librets/librets/trunk@1563 fe7ac059-47f5-0310-8599-d0339b4e125c
Update csharp and java for Windows

git-svn-id: https://code.crt.realtors.org/svn/librets/librets/trunk@1564 fe7ac059-47f5-0310-8599-d0339b4e125c