Removed all traces of old code dependent on clap.base import from `clap.checker.Checker()`
Removed all traces of old clap.parser.Parser from tests.py
(these will later be added when the code from clap.modes will
be moved to clap.parser but now it's convinient)
Fixed bug which caused a crash in clap.modes.Parser if it contained options which had no arguments
Mode information are now private
Fixed a typo in docstring in clap/base.py
Removed unused debug print() message (it was telling the type of checked
parser)
Merged ParserTests and ModesTests
Information about parsed options and operands are now private and
should be accessed via getters()
Unified single and nested-mode parsers, clap.modes.Parser is now
officially deprecated