Add .gitignore adapted from MPC-HC

Also remove some *.user files from the repo
Added VS2012/VS2013 compilation

* No additional projects were used, meaning VS2010, VS2012 and VS2013 are now sharing them same project files. Solution files are identical, except for the first two lines.
* Be advised that we may need additional changes in order to compile with VS2013, compilation was only successfully tested with VS2012.
* I made an effort to consolidade common properties and remove useless/redundant ones from every project file. As a bonus, this fixed some warnings in debug builds.
* Unused/outdated project and solution files were removed.
* The build_vsfilter.sh file was updated to support the compilation with newer VS versions.
* A small change was made to log4cplus in order to make it compile with VS2012 (added "functional" include to configurator.cxx).
* Chinese text in *.filters files was replaced with their English counterparts.
Moved/renamed project files to not contain references to VS versions
Projects: move configuration properties to the right place
Use only one solution file

The solution file can be shared across VS (2010-2013) versions if you specify the minimum supported version at the beginning of the file (i.e. VS won't ask you to upgrade the solution file).
Merge identical properties in project files
Fix VS2013 build
Fix VS2010 build and change defines to proper hex
Fixed build script for VS2012+
Moved PlatformToolset property to external file

Also, changed PlatformToolset to the XP-compatible version.
Some fixes for project files

* Added define to avoid MFC bloat in VS2012+
* Only use old MFC bloat fix hack in VS2010
* Fixed "${ProjectName}" -> "$(ProjectName)"
* Set "WINVER=0x0601" and "PSAPI_VERSION=1" defines for VS2010+ for now(?)
Use separate IntDirs and OutDirs for different VS versions

Also, simplify some MSBuild conditions
Clean up common.props to remove unused configurations like "Release Filter" and "Release Lite" which only exist in MPC-HC.
Convert MFC-using stuff to Unicode
Couple project fixes

* Set SubSystem to VSFilter projects
* Build with /Gw in VS2013
Move VSFilter.sln to the root dir
Add gtest dependency to the unit_test project
Build script fixes

* Abort on invalid compiler arguments (don't fall back on VS2013)
* Accept lowercase values for the compiler argument
Add leftover changes from f87ac12440a022da9deee2a8ae9daedf71ee6829

Also, ignore BaseClasses *.asm files generated by Visual Studio
Fix log4plus properties file and move all merged properties there