Avoid Boost dependencies if the functionality comes with C++11

[philipp-classen]

(issue migrated from grogers0/CppQuickCheck)

We already have C++11 as a requirement. Some aspects, which are currently implemented via Boost, could now be replaced. For instance:

• Random number generators
• boost::tuple
• boost::bind
• boost::function

For now, I would avoid upgrading to C++14 unless there is a significant need. However, starting to gradually migrate straightforward parts (currently implemented with Boost) to C++11 should simplify the maintenance in the long run.

From what I see, it would eliminate the need for Boost. Although a dependency to Boost is not really harmful, we should avoid it if all functionality that we are using comes now with C++11.