ENH: Framework for java dependency scanner.  Right now it does nothing but always reports success.  This is enough to get the Java test to pass with the new generator because the old implementation did not do dependencies anyway.

ENH: add a new library path ordering algorithm to make sure -L paths will pick the correct libraries if possible

ENH: Changed over to using C++ for building flex/bison generated files.  It reduces the number of changes that need to be made after generation.

ENH: Split dependency scanning and checking into separate cmDepends superclass with language-specific subclasses such as cmDependsC.

ENH: Re-implemented cmGeneratedFileStream to look like a real stream and replace the destination file atomically.  This will avoid problems with the process being terminated while generating a file.