Issue 1011 model new copy

[valentinsulzer]

Description

Reformat model.new_copy() to maintain submodels. Also removes some methods from Simulation to keep things simpler.

Fixes #1011

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ flake8
• All tests pass: $ python run-tests.py --unit
• The documentation builds: $ cd docs and then $ make clean; make html

You can run all three at once, using $ python run-tests.py --quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Merging #1090 into develop will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #1090      +/-   ##
===========================================
- Coverage    97.78%   97.76%   -0.02%     
===========================================
  Files          242      243       +1     
  Lines        12658    12664       +6     
===========================================
+ Hits         12377    12381       +4     
- Misses         281      283       +2     

Impacted Files	Coverage Δ
pybamm/models/base_model.py	98.84% <100.00%> (+0.02%)	⬆️
...m/models/full_battery_models/base_battery_model.py	98.97% <100.00%> (+0.07%)	⬆️
...models/full_battery_models/lead_acid/basic_full.py	100.00% <100.00%> (ø)
...odels/full_battery_models/lithium_ion/basic_dfn.py	100.00% <100.00%> (ø)
...odels/full_battery_models/lithium_ion/basic_spm.py	100.00% <100.00%> (ø)
...bamm/models/submodels/external_circuit/__init__.py	100.00% <100.00%> (ø)
...ls/submodels/external_circuit/experiment_events.py	100.00% <100.00%> (ø)
pybamm/simulation.py	96.78% <100.00%> (-1.23%)	⬇️
pybamm/solvers/base_solver.py	100.00% <100.00%> (ø)
... and 1 more

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[brosaplanella]

Looks good, thanks!

[brosaplanella]

Does the current cut-off need to be added to the parameter values or does it get a default value if unspecified?

[valentinsulzer]

It's an input parameter so needs to be provided by the user when solving. But the experiment class does this automatically.

[rtimms]

thanks @tinosulzer !