Doxygen config

Add doxygen config to generate documentation from source tree.
Also add document generate directory into gitignore list.
GUI part initial commit

Including resource images, wxFormBuilder project, generated code, and a
custom wxWidgets component called wxCvPanel.
Library part initial commit

These are components that will be used by main program.  This commit
includes OpenCV wrappers and some miscellaneous utilites, and CMake
build script for both.

Note this commit does not support Window.  I'm currently only testing
the program on Linux.
Main program initial commit

This includes GUI implementation and core implementation.  I tried
separating core logic from GUI logic as much as possible, hence the two
components in main program.

The main program is not very stable.  It contains some bugs that I've
not yet come up with a solution.  Also, some functionalities have not
been implemented yet.

Well, somehow I admit that I've made the program overly complex.
CMake build script

Finally, the CMake build script is here.

As stated in previous commit, there's no Windows support at this time,
because I have not yet tested the program on Windows.