default blocked proportion for record linkage = .5
blocked sampling for record linkage #318
sampling tweaks WIP
more recordlink blocked sampling WIP
faster recordlink blocked sampling
a little cleaning up
formatting
factor out frozenDict method
faster check for frozen
reduce copying of potentially huge objects, tests
clean up print statements
compatibility with python 2.6
fix coveralls
2.6 bug
add coverage to requirements
try different test
Merge pull request #320 from datamade/recordlink-sampling

Recordlink sampling, close #318