Gdsfactory

- keep python3.7 compatibility for `gf.functions.cache` decorator by using `cache = lru_cache(maxsize=None)` instead of `cache = lru_cache`
- `add_fiber_array` accepts ComponentOrFactory, convenient for testing the function without building a component

- fix clean_name
- generators and iterables are properly hashed now
- toolz.compose functions hash both the functions and first function
- casting foats to ints when possible, so straight(length=5) and straight(length=5.0) return the same component
- set Component.\_cached = True when adding Component into cache, and raises MutabilityError when adding any element to it.
- Component.flatten() returns a copy of the component, that includes the flattened component. New name adds `_flat` suffix to original name
- add bias to grating_coupler_lumerical
- try to cast float to int when exporting info
- remove `ComponentSweep` as it was trivial to define as a list comprehension
- remove `add_text` as it is prone to creating mutability errors
- pack can now add text labels if passed a text ComponentFactory

- `add_fiber_single` allows to have multiple gratings
- converted add_fiber_single, component_sequence and add_fiber_array from `cell_without_validator` to `cell`
- Component pydantic validator accepts cell names below 100 characters (before it was forcing 32)

- rename doe, write_does and load_does to `sweep` module `read_sweep`, `write_sweep` ...
- Route and Routes are pydantic.BaseModel instead of dataclasses
- composed functions get a unique name. You can compose functions with `toolz.compose`
- add `gf.add_text` for adding text labels to a list of Components
- add `gf.typings.ComponentSweep`
- increase MAX_NAME_LENGTH to 100 characters when validating a component
- add typing_extensions to requirements to keep 3.7 compatibility. Changed `from typing import Literal` (requires python>=3.8) to `from typing_extensions import Literal`
- add type checking error messages for Component and ComponentReference
- add type checking pydantic validator for Label
- replace `phidl.device_layout.Label` with `gf.Label`
- Route has an Optional list of Label, in case route fails, or in case you want to add connectivity labels

- add slab arguments (slab_layer, slab_xmin) to grating couplers
- remove align to bottom left in gdsdiff
- gdsdiff after asking question, re-rises GeometryDifferencesError

- fix gdsfactory/samples
- better docstrings documents `keyword Args` as well as `Args`
- refactor:
- pads_shorted accepts pad as parameter
- rename `n_devices` to columns in splitter_chain
- rename `dbr2` to `dbr_tapered`
- simpler pn cross_section definition