Merge branch 'master' into release
Merge branch 'master_python2.3' into release_python2.3
Merge branch 'release'
Merge branch 'release_python2.3' into master_python2.3
Added pointer to the doc of ufloat(), so that people encounter NaN standard deviations.
Merge branch 'master_python2.3'
Merge branch 'master' into master_python2.3