implemented .revoked
Theory#solve without a block
added coverage to logic
updated checkmate example
removed 'set' dependency
refactoring arithmetics
refactored requires, renoved .together(), separated .ensure()
Merge branch 'refactoring' into assumption
separated theory into modules
Merge branch 'refactoring' into rspec
added release notes
refactored specs, improved rspec integration
migrating logic/ tests to rspec/
refactored error messages
refactoring logic to rspec
migrated logics to specs
updated specs, changed location of rspec integration
updated old specs
started mice example
added some missing types of assumptions