remove boost dependency

[Trass3r]

would be nice not having to pull in that monster

[fhoefling]

We're using the wrapper mostly in HALMD, and there Boost is needed anyway. Sure, it would be nice to get rid of it. At the same time, it would be nice to switch to C++11, which would simplify some things. But I don't have time to care about such stuff.

Of course, your are welcome to contribute improvements to the package.