* Add pytato.squeeze

* add test

* use are_shape_components_equal

Co-authored-by: Kaushik Kulkarni <15399010+kaushikcfd@users.noreply.github.com>

* fix

* Add random graph generation

* push current state

* Random DAG generator actually tests things

* Fix show_dot_graph invocation that tripped up pylint

* DataInterface: document dtype, shape as read-only

* Type-annotate, type-check testlib

* Style/name/comment fixes from Kaushik's review

Co-authored-by: [6~ <inform@tiker.net>
Co-authored-by: Kaushik Kulkarni <15399010+kaushikcfd@users.noreply.github.com>

* mypy show error codes

Co-authored-by: Andreas Kloeckner <inform@tiker.net>

* gets rid of unnecessary type-ignore

* dim_to_index_lambda_components: makes interface more convenient

caller can pass None for variable name generator, in which the routine will
create a unique name generator of its own.

* call_loopy: shape inference implementation

Co-authored-by: Andreas Kloeckner <inform@tiker.net>

* test call_loopy with shape inference

* move SizeParamGatherer to pytato.transform

* starts being less invasive about overwriting dtypes

* Add, clean up *Gatherer docs

Co-authored-by: Andreas Kloeckner <inform@tiker.net>