Nspyre

- Fix bug in the flex line plot widget where the plot axis labels and title were not showing

CHANGELOG:
- New StreamingList class allows much more efficient data streaming to the data server
- New InstrumentManager class consolidates connections to multiple InstrumentGateways.
- New InstrumentGatewayDevice class (this gets returned by InstrumentGateway!); solves some issues related to instrument server disconnects
- New Subsystem class to help with boot sequencing of drivers
- Overhaul FlexLinePlot to be properly threadsafe
- Allow user to add custom data processing to FlexLinePlot (data_processing_fun)
- Change inserv_cli() to serve_instrument_server_cli()
- Make save/load widgets asynchronous with threads (and add pop() timeout)
- Fix logging issues related to starting the experiment subprocess - experiments need to call nspyre_init_logging in subprocess; see template repo for usage example
- Fix bugs in colormap (and rename to HeatMap)

See the API docs for more details on new functionality, and the template repo (https://github.com/nspyre-org/template) for usage examples.

CHANGELOG:
- Too many to list
- Total overhaul of the project with a new API

CHANGELOG:

**Other**
- modified the creation of the universal _Pint Unit Registry_ to use `get_application_registry` in case the user has already created a _Units Registry_ in the program at a prior point of execution

CHANGELOG:

**Other**
- fixed RPyC connection issues by modifying the _timeouts_ to appropriate times to give the server time to send and receive packets

CHANGELOG:

**Spyrelets**
- the `Spyrelet` class now appropriately handles _args_ and _kwargs_; client config files now accept both _args_ and _kwargs_
- fixed `enforce_args_units` error not checking _PARAMS_ correctly for assigning default values; renamed `enforce_args_units` to a dunder method
- changed `Spyrelet` _unique_name_ and _gateway_ back to _args_ from _kwargs_, otherwise object breaks if none are specified

**General GUI**
- moved `QApplication` QSS styling to dedicated style sheet
- fixed 'spyrelet manager' _WindowTitle_ displaying wrong text; it now displays the currently active `Spyrelet`
- minor GUI code refactoring and cleanup

**Instrument Manager**
- fixed issue on initialization giving wrong _step size_ units
- added _'refresh all' button_ that manually triggers an update to all driver attributes for each device
- added a visual notification to attributes when they change (briefly flash green when they are updated); this also provides a confirmation that a user set value has been successful applied
- added tooltips displaying _docstrings_ for the `Feats`, `DictFeats`, and `Actions` in the _Instrument Manager_.
- removed _Actions_ that take arguments from displaying in the _Instrument Manager_
- modified scroll wheel behavior in the _Instrument Manager_ to prevent accidental setting of values.
- minor Qt rendering performance improvements

**View Manager**
- fixed an issue with the initial GUI window size when starting up
- added a delay to updating plots to prevent lock ups with datasets that update frequently
- added error bar plotting to `LinePlotView`
- basic refactoring and cleanup

**Other**
- improved namespace hierarchy to simplify import statements
- set `__all__` variable and module imports in `__init__.py` for subpackages to allow for cleaner imports and explicitly define user API functions
- extensive namespace cleanup and import statement refactoring
- added deprecation decorator to `misc` module
- Renamed `debug_qt` to `qt_set_trace`
- minor documentation updates
- small refactoring to various files