Warn and exit if both -j and -k are passed as these are exclusive options

This is in response #93, but I have seen this mistake else where as well.
Add lua info to building part of readme
Increment version to 0.84 for release
Increment version to 0.85.0 to development version
Fix CPPFLAGS propagation by saving it in m4/ax_lib_geos.m4
Remove non-necessary echo in m4/ax_lib_geos.m4
Merge pull request #103 from jocelynj/cppflags

Fix CPPFLAGS propagation in configure script
Reword 9.1+2.0 suggestions

Frederik's testing showed 9.1+2.0 is substantially faster than 8.4+1.5, so word the paragraph stronger. At this point 8.4+1.5 is old and 8.4 will reach EOL in July 2014.
Merge pull request #113 from pnorman/patch-4

Reword 9.1+2.0 suggestions
Merge pull request #95 from pnorman/patch-2

Add lua info to building part of readme
Fix small typo (tunel to tunnel) in the lua style to make sure the z_order is correct
Merge pull request #114 from jimmyrocks/master

Fix small typo (tunel to tunnel) in the style.lua file to make sure the z_ord...
Fork not supported on MinGW.
Added additional logic to properly detect mingw. More udpates for supporting custom protobuf-c paths. Mthread support detection updates.
MinGW also requires GEOS_INLINE.
Updates to support custom protobuf-c paths on mingw. Old logic was self sabotaging itself by resetting includes to nothing when the inc/lib specific flags were specified to configure.
Not sure why __MINGW_H macro is used. __MINGW32__ or __MINGW__ are the standard widely used macros. I couldn't get osm2psql to build with the _H macro. I went forward using _MINGW32__, which is what you see in most open source ports to this platform.
Moved config.h header down the headers list so the VERSION and PACKAGE_VERSION macros wouldn't interfere with osm2pgsqls.
Revert pthread updates.
Make sure any protobuf-c dependencies are included after.