Boolean operators or(Option) and(Option), code style

Boolean operator or(Option[LogicalBoolean]) introduced.

Code style improvements:
* removed unnecessary ";" at the end of line
* made the code style for FalseLogicalBoolean and TrueLogicalBoolean the same
* made FalseLogicalBoolean an object, not a class
* removed unnecessary "ConstantLogicalBoolean" trait withoud a body and with only two obvious parents.
* other small things

Improved test coverage for True/False and added tests for and(Option), or(Option)