Add relative and absolute stop tolerances.
Add logger and simplify sbmin driver.
Cosmetic changes.
Simplifications to sbmin.
Merge branch 'lancelot-dev' of git://github.com/lambe/nlpy into lancelot-dev

Conflicts:
	nlpy/optimize/solvers/nlpy_sbmin.py
	nlpy/optimize/solvers/sbmin.py
	nlpy/optimize/tr/trustregion.py
Refine pcg output.
Big cleanup of BQP.
Big cleanup of sbmin driver.
Minor changes in sbmin.
Cosmetic changes.
Safeguarded Min() and Max().
Update objective value in TruncatedCG.
Suppress useless PCG output.
Simplify feasibility check + impose decrease during extrapolation.
Minor fixed in sbmin driver.
Properly initialize msxiter.
ANew attribute pHp.
Resolve cyclic import.
Simplifications using break points.
Improve SBMIN driver.