vs project settings and build version definition correction

This change fixes several issues with the Visual Studio 2012 build files.

It corrects an issue with the VERSION definition in zlibvc.def.

It adjusts the project build settings to build the x86 and x86_64 versions consistently. The current version statically links the x86 build and dynamically links the x86_64 build (this causes the 64-bit build to depend on the msvcrN redistributable).

It disables the SEH check.

It increases the optimization level to full.