Improve DataFrames, transformer deco, add no effect checkpoint

Cotransform dict DataFrames, improve transformer deco, add no effect …

…checkpoint (#30)

* setup fugue sql

* SQL: add basic extensions and tests

* update

* update

* clean up sql files

* fix syntax, add save load

* add test for load

* FugueSQLWorkflow

* update version

* Add pandas udf support, add SQL persist broadcast

* update

* update

* update

* update

* update

* make transformer schema more flexible

* Remove ABC from Transformers

* cotransform on dict like dataframes, add no effect checkpoint

* change deco lambda

* add more tests