From nengo_loihi.inputs. These classes are only used as part of
the build process and should not be made alongside Block and
LoihiInput instances.

Also corrects an incorrect default in the simulator docstring.

The test was fragile with the old tolerances, failing for many seeds.

Most of the work done by the splitter is now done in the builder.
This should give more clarity and control over the mapping between
pre-build and post-build objects. The `Split` class takes on the
organizational tasks of the old `Splitter`, giving directives to
the builder about what should be on- or off-chip.

Several tests were added or modified to ensure that these changes
did not affect built models in adverse ways. Some tests were added
to ensure that the refactoring made improvements; for example, the
refactored splitter no longer mutates networks, which closes #211.
Simulations should now be identical whether precompute is True
or False, so the tolerance in test_precompute is now set to zero.

The passthrough removal process was also modified to act in the
same way as `Split`, and is now named `PassthroughSplit` accordingly.

Co-authored-by: Trevor Bekolay <tbekolay@gmail.com>

Also fix an issue caught by flake8

Closes #205 and #206.

The decoder cache does not work for host models due to having
no context manager, which is normally constructed by the
top-level network builder.

This commit fixes #207 as it does not globally disable the
decoder cache. We also add some asserts to existing tests
for ensure that #207 is fixed.

Fixes #208 and #209.

Covers some previously uncovered lines in `conv.py`.

There were a few places where we were raising errors that were
not subclasses of NengoException. They are now appropriate
NengoExceptions.

A keyword argument changed in a recent abr_control commit.

This partially reverts commit
70ecb8a.

The patch to graph.Graph seems to be incomplete, as one process
could be writing to the file to be copied while another process
is attempting to read it. The includes are also not copied, so
likely we need a more robust solution for writing snip files to
temporary directories.

The command was only changed to request one worker instead of two.