Firebird 2.5 Patch to compile with Visual Studio 2015

Final Firebird 2.5 Patch to compile with Visual Studio 2015 is now merged
https://github.com/FirebirdSQL/firebird/pull/12

I will add a gerrit for libreoffice also https://patch-diff.githubusercontent.com/raw/FirebirdSQL/firebird/pull/12.patch

Gerrit for this patch is now created and added Lionel to the reviewers

https://gerrit.libreoffice.org/#/c/23738/


update: added patch with mod_loader changes for VC14 ,
removed external/firebird/firebird-vs2013.patch.1 is not needed anymore in 2.5.5 (applied upstream) ,

modified UnpackedTarball_firebird.mk apply firebird-msvc14.patch.1 only on Windows

ps: in Firebird tree i will send a pull request with icu small changes needed also new solutions for VS 2015 were merged earlier