Removing syntax constructs unsupported in rspec 3

- be_false/be_true matchers replaced
- When expecting block not to throw expection, arguments cannot be used. I.e., any expection violates the expectation.
- have() matcher unsupported. Replaced with .count() method.
Merge pull request #8 from sustr4/rspec3

Removing syntax constructs unsupported in rspec 3