* Allow different names for ...rest
* Resolves#3945
* This change requires an explicit name for the rest argument in `WholeStreamCommand`,
which is why there are so many changed files.
* Remove redundant clone
* Add tests
* nuframe in its own type in UntaggedValue
* Removed eager dataframe from enum
* Dataframe created from list of values
* Corrected order in dataframe columns
* Returned tag from stream collection
* Removed series from dataframe commands
* Arithmetic operators
* forced push
* forced push
* Replace all command
* String commands
* appending operations with dfs
* Testing suite for dataframes
* Unit test for dataframe commands
* improved equality for dataframes
* moving all dataframe operations to protocol
* objects in dataframes
* Removed cloning when converting to row
* nuframe in its own type in UntaggedValue
* Removed eager dataframe from enum
* Dataframe created from list of values
* Corrected order in dataframe columns
* Returned tag from stream collection
* Removed series from dataframe commands
* Arithmetic operators
* forced push
* forced push
* Replace all command
* String commands
* appending operations with dfs
* Testing suite for dataframes
* Unit test for dataframe commands
* improved equality for dataframes
* moving all dataframe operations to protocol
* nuframe in its own type in UntaggedValue
* Removed eager dataframe from enum
* Dataframe created from list of values
* Corrected order in dataframe columns
* Returned tag from stream collection
* Removed series from dataframe commands
* Arithmetic operators
* forced push
* forced push
* Replace all command
* String commands
* appending operations with dfs
* Testing suite for dataframes
* Unit test for dataframe commands
* improved equality for dataframes