Removed old matroska implementation (to be replaced by a new one)
Removed matroska files from CMakeLists.txt
Added again the old ebmlconstants.h
Added EBMLFile header and implementation
Added EBMLElement header and implementation (NOTE: Work in progress, will be completed later)
Added uncomplete EBML testcase with empty ebml file
Add currently available EBML files to the CMake build system