SSMProblems integration

[FredericWantiez]

The two main issues I see with the current API in SSMProblems:

• Handling of observations, I wrapped them up in the model and the user has to deal with it.
• Couldn't easily remove AdvancedPS.isdone

Fixes: #93; Fixes: #94

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.60%. Comparing base (1e5dfdd) to head (804bda0).

❗ Current head 804bda0 differs from pull request most recent head e834cd9. Consider uploading reports for the commit e834cd9 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #97      +/-   ##
==========================================
- Coverage   96.09%   95.60%   -0.49%     
==========================================
  Files           8        8              
  Lines         410      410              
==========================================
- Hits          394      392       -2     
- Misses         16       18       +2     

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[coveralls]

Pull Request Test Coverage Report for Build 8667027991

Details

• 6 of 6 (100.0%) changed or added relevant lines in 3 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.5%) to 95.61%

---

Files with Coverage Reduction	New Missed Lines	%
ext/AdvancedPSLibtaskExt.jl	2	91.25%

Totals
Change from base Build 6816722471:	-0.5%
Covered Lines:	392
Relevant Lines:	410

---

💛 - Coveralls

[THargreaves]

This looks good to me. Happy for this to replace the previous partial PRs.

Wrapping the observations in the model seems like a sensible approach for now.

[FredericWantiez]

@yebai

[yebai]

Thanks @FredericWantiez, good work! Feel free to merge this!