combiner: join two tables
combiner: refactor to Join transform
transforms: Join: linting errors
transforms: use iota for join types
transforms: add test for Left join
combiner: fix broken test TestTableTransformError
combiner: use go routine in Join
combiner: update join to use struct for cleaner enum behavior
Merge pull request #1 from nathanleiby/combiner

combiner: combine two tables via join or extend