Better output reader

[keurfonluu]

• Added: option n_variables to define the number of primary variables for the reader.
• Added: some features for iTOUGH2 (e.g., block DIMEN, MOMOP(50)...).
• Changed: more robust standard TOUGH output reader, especially for different versions of TOUGH.

Reminders:

• [x] Run invoke format to make sure the code follows the style guide,
• [x] Add tests for new features or tests that would have caught the bug that you're fixing,
• [x] Write detailed docstrings for all functions, classes and/or methods,
• [x] If adding new functionality, unit test it and add it to the documentation.

[codecov[bot]]

Codecov Report

Patch coverage: 97.39% and project coverage change: +0.07 :tada:

Comparison is base (6b2a0f8) 91.03% compared to head (8602413) 91.10%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #135 +/- ## ========================================== + Coverage 91.03% 91.10% +0.07% ========================================== Files 86 86 Lines 5900 5960 +60 ========================================== + Hits 5371 5430 +59 - Misses 529 530 +1 ``` | [Impacted Files](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu) | Coverage Δ | | |---|---|---| | [toughio/\_common.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9fY29tbW9uLnB5) | `95.65% <ø> (ø)` | | | [toughio/\_io/input/\_helpers.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vaW5wdXQvX2hlbHBlcnMucHk=) | `84.37% <ø> (ø)` | | | [toughio/\_io/input/tough/\_write.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vaW5wdXQvdG91Z2gvX3dyaXRlLnB5) | `93.91% <93.75%> (-0.02%)` | :arrow_down: | | [toughio/\_io/output/tough/\_tough.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vb3V0cHV0L3RvdWdoL190b3VnaC5weQ==) | `80.19% <95.12%> (+4.85%)` | :arrow_up: | | [toughio/\_cli/\_extract.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9fY2xpL19leHRyYWN0LnB5) | `85.71% <100.00%> (ø)` | | | [toughio/\_io/input/tough/\_common.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vaW5wdXQvdG91Z2gvX2NvbW1vbi5weQ==) | `100.00% <100.00%> (ø)` | | | [toughio/\_io/input/tough/\_helpers.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vaW5wdXQvdG91Z2gvX2hlbHBlcnMucHk=) | `95.34% <100.00%> (ø)` | | | [toughio/\_io/input/tough/\_read.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vaW5wdXQvdG91Z2gvX3JlYWQucHk=) | `96.11% <100.00%> (+0.10%)` | :arrow_up: | | [toughio/\_io/output/\_helpers.py](https://codecov.io/gh/keurfonluu/toughio/pull/135?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu#diff-dG91Z2hpby9faW8vb3V0cHV0L19oZWxwZXJzLnB5) | `87.69% <100.00%> (-0.37%)` | :arrow_down: | ... and [2 files with indirect coverage changes](https://codecov.io/gh/keurfonluu/toughio/pull/135/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu) Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Keurfon+Luu)

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