Retrieve parent data, matching to a nested (child) dataset by keys of a nested dataset exported from an ODK Aggregate Server.
Source:R/nestedSurvey.R
      mergeNestedODK.RdRetrieve parent data, matching to a nested (child) dataset by keys of a nested dataset exported from an ODK Aggregate Server.
Arguments
- parent
- Data frame of household data 
- child
- Data frame of child (repeat) data 
- byPARENT_KEY
- Should data frames be matched based on PARENT_KEY (child) and KEY (parent) columns? (Currently only option is TRUE) 
- removeCols
- Character vector of column names to remove from the parent data frame (optional) 
- removeRows
- Index of which rows should be removed from child data frame (optional)