Transparently load state variables from disk in standalone scripts. Closes #177
Adapt monitors to work with the transparent state variable loading introduced in the previous commit.
Adapt tests and examples to the new transparent state variable loading in standalone.
Update the docs for the transparent variable loading in standalone.
Rename `Group.runner` to `Group.custom_operation`. Closes #220
Merge pull request #275 from brian-team/rename_runner

Rename `Group.runner` to `Group.custom_operation`.
Fix for windows
Merge pull request #272 from brian-team/standalone_read_variables

Standalone read variables
Be a bit more careful when linking to index variables and allow some references to pre/post variables to not be available in synapses because of too complicated indexing
Fix an issue surrounding scalar variables and referenced subexpressions. Also explicitly raise a NotImplementedError when trying to use a linked variable with a subexpression -- before it failed with an opaque error message
Make the `report` argument in `Network.run` do what the docs promise
Implement progress reporting for the C++ standalone. Closes #257
Add some basic tests for progress reporting (runtime only)
Make the default `report_period` in `run` consistent with `Network.run`
Document progress reporting
Merge pull request #279 from brian-team/progress_report

Progress reporting
Merge pull request #277 from brian-team/linked_var_synapses_fix

Be a bit more careful when linking to index variable
Allow subgroups of subgroups. Closes #280
Better error message for reset and threshold when specifying a single value instead of a string (Brian1 syntax)
Automatically convert e.g. lists to Quantity objects (if possible) in the check_units decorator and give more useful error messages in case conversion fails