Change log <2/18/09>:
(1) Change default ic from "SIC" to "AIC" in scobs.R: Since "SIC" performs 
better in quantile smoothing spline while "AIC" usually is better for knots 
selection in quantile regression spline.
(2) Change ptConstr$equal, $smaller, etc. on drqssbc.R line 52-55: Since
".splineBasis" in both l1.design2 and loo.design2 expects "x" to be sorted 
according to the order of x, so we need to sort "y" according to the order
of "x" as well in the pseudo "Y" observation.
(3) Change the number of gradient constraint to two times n.gradient in
drqssbc.R line 118: There should be two inequality constraints passed to 
'rq.fit.sfn' or 'rq.fit.sfnc' for each specified equality constraint.
(4) Add an additional argument "nk.start" to cobs, qbsks2 to 
allow the possibility of having the minimum number of starting knots to be
different from the default value of 2:  This is to avoid scenario where
there are too many 'pointwise' constraints that requires more knots than
the default number of 2. Otherwise, rq.fit.sfnc will retunr NaN in coefficients
(5) Updated cobs.Rd and qbsks.Rd to include description of nk.start
(6) Update cobs.Rd to include the reference to Ng and Maechler (2007).