allow exclusive bounds

[mb706]

some learners in mlr allow for ranges of numeric parameters with exclusive bounds. This is currently worked around using .Machine$double.eps (and fails if the absolute value of the bound is >= 2), and should have a proper solution. I suggest parameters (and defaults) inclusive.bounds = TRUE, inclusive.bound.lower = inclusive.bounds, inclusive.bound.upper = inclusive.bounds.

[berndbischl]

yeah, i thought about this some time ago, then kinda was too lazy to do this.

i guess we could add this