This class provide simple and easy way for retrieving data from configuration
file, and parsing by sections (if exist) and keys with values. Comment line
begining with #, section name concluded in brackets [ and ], key separated
from value by =. All those simbols defaults and can be changed when instance
created.
Comments, empty line, empty sections, keys without values are ignored. All
spaces around sections name, keys and values deleted, but not touched inside.