add functions for sampling with equal prob
Merge branch 'master' into dh/sample
add Fisher-Yates sampler
Merge branch 'master' into dh/sample
use revised randi in Fisher-Yates shuffling
self-avoid sample and other tweaks
Merge branch 'master' into dh/sample
add weighted sampling
add tests and fix bugs
renamed sample to sample for weighted sampling
relax the criterion for matrix distribution testing
Merge pull request #108 from JuliaStats/dh/sample

New sample function