@brief Read the description of the kml file
@param filename The filename to check
@return The description of the file
@brief Read the content of the kml file
@param filename The filename to check
@return The content of the file
@brief Read the name of the kml file
@param filename The filename to check
@return The name of the file
@brief Read the version of the kml file
@param filename The filename to check
@return The version of the file
@brief Validate the kml file
@param filename The filename to check
@return true if the file is valid, false otherwise