Adjust NA handling strategy in match_on.glm.
adding a match_on.glm test with an attached data.frame
match_on.glm should attempt to use the data from the glm when possible, falling back to model.frame on the formula
Clarified some test explanations
data argument no longer needed to summary for RItools integration
Merge remote-tracking branch 'origin/master' into issue83
Merge branch 'issue83'
Merge branch 'issue83'