Set DebugInformationFormat consistently in all projects

Use the "Program Database (/Zi)" in release mode and in debug
mode for x64, use "Program Database for Edit & Continue (/ZI)"
in debug mode for Win32.

This is how new visual studio projects are set by default.
Merge pull request #1124 from mstorsjo/consistent-debug-options

Set DebugInformationFormat consistently in all projects