Sorting.indexSort overload for the Float array

It was missing orginally
Merge pull request #322 from eiennohito/patch-1

Sorting.indexSort overload for the Float array
cdfs and inverse cdfs for the easy tests
tests for HasCdf
an actual cdf function!
Merge remote-tracking branch 'scalanlp/master'
actually use the implicit random number generator. closes #319
added a “mapActive” method to zipMapKeyValues, should be faster for OWLQN (#326).

Also optimized zipMap for SparseVector when f(0, 0) == 0.
missed an exp in NegativeBinomial
use gallop search instead of binarySearch for dot products. much faster in nearly all cases
benchmarks for SparseVector#dot
so linear search for small arrays doesn’t seem to help
switch between “smart” loop for big sparse vectors, and simple loop for small ones
NNLS and QuadraticMinimizer refactored to breeze; testcases added for different qp variants;runtime comparisons on randomly generated quadratic problems
Merge branch 'master' of https://github.com/scalanlp/breeze into qp