test for a _constructSection() method has been added
class Section has been changed
currentLevel pointer has been added
class TokenMark for marking of tokens' level has been added
_markAllTokens() method has been added
marked tokens collection has been added to a parser
_markAllTokens() has been implemented
test for a _markAllTokens() method has been added. _markAllTokens() method has been fixed
new test for _markAllTokens() method has been added