Adding metadata interface
    
    This patch:
    1) Adds the definition of the metadata interface
    to the header file. The functions that were exposed
    for no good reason are now hidden.
    2) Previously exposed functions and their descriptions
    are removed from the public header and placed into
    the source code for now.
    3) The function that reads the config file no longer
    tries to close file in case of error.
    4) Lines collection is still passed in into the reading
    function but as a collection itself not as a pointer
    to it.
    5) All the parts related to processing lines are currently
    ifdefed using HAVE_VALIDATION that is currently is not defined.
    This is done to disable creation of the lines collection
    utill it is actually needed. I did not want to blindly remove
    it though and loose already done work that will be useful
    in future.
    6) Version of the library and interface is updated
    7) New header and source modules are introduced to hold functions
    related to the meta data. They are mostly stubbed out.
    
    This is incomplete patch. It builds and make check runs.
    It is created just to simplify the review a bit.