Add more contents to LinearFrictionConeWrenchConstaint
1. Add a method contactPosition to ContactWrenchConstraint
2. Finish implementation of LinearFrictionConeWrenchConstraint. Add its test
Start to work on a new constraint type, RailGraspWrenchConstraint
1. Finish implementing RailGraspWrenchConstraint in MATLAB
2. evalSparseStructure does not return number of rows or columns. These two quantities should be obtained through other functions
more progress on windows compilation.  documented in https://github.com/RobotLocomotion/drake/issues/42
1.Change the hierarchy of the RigidBodyConstraint, now robot and tspan are shared by the RigidBodyConstraint
2.Delete 'setActive' method in QuasiStaticConstraint, it is confusing
Now RigidBodyConstraint has property 'robot','tspan' and 'mex_ptr'.
Fix a bug in inverseKinBackend. Restore the 'active' property in QuasiStaticConstraint
JLCMCoder coordinateNames() method converst java string array to cell array
got rid of matlab_cpu dependency (since it's hard to get on windows, and wasn't actually being used!)
close to working matlabroot logic
find mex executables on windows by looking for .bat files explicitly.
compiler checks work for visual studio
mex argument processing starting to work for visual studio (still need to handle all the arguments)
added mex compiler options for visual studio
have to compile on windows with make then cd pod-build, nmake.  but it's finally working to the point that i'm getting useful errors/warnings from the compiler
progress on building for windows
handle paths with whitespace
moving cmake to submodule
pulling in cmake submodule
adding release filelist logic