added CudaMem support to Input/Output arrays
renamed gpu headers (made it more consistent)
removed obsolete DevMem2D class
added Stream support to ogl::Buffer
moved inline implementation to separate file
moved GpuMat implementation to separate file
refactored GpuMat:

* switch to InputArray/OutputArray
* add Stream support
new implementation for GpuMat::setTo (without constant memory)
refactored CudaMem (now alloc type assign only in constructor)
refactored gpu::Stream (minor fixes)
refactored gpu info structures (TargetArchs and DeviceInfo)

now DeviceInfo provides full information about device (from cudaDeviceProp)
restored old header files for source compatibility
added Event class (wrapper for cudaEvent)
made createContinuous & ensureSizeIsEnough generic (OutputArray support)