Implement clipping on beta

[oooo26]

• Implement clipping after each primary fitting, see #510 ;
• Add relative pytest;
• R API should be updated for two new parameters beta_low, beta_high; (TODO)

[Mamba413]

@oooo26 , I have just seen the test file. If either beta_low or beta_high is set, any bug will occur?

[oooo26]

@oooo26 , I have just seen the test file. If either beta_low or beta_high is set, any bug will occur?

Thank you for checking! There is no bug. But let me add more tests on that.

[oooo26]

And please also note that:

• C++ code allows beta_low>beta_high, but it will ignore the beta range limitation if so. Python side will check and raise error;
• If enable normalization, the final beta would be possible to outside the range limitation. Because clipping is implemented during fitting.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.01% :tada:

Comparison is base (9c97655) 97.73% compared to head (9b40936) 97.74%. Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #516 +/- ## ========================================== + Coverage 97.73% 97.74% +0.01% ========================================== Files 7 7 Lines 970 977 +7 ========================================== + Hits 948 955 +7 Misses 22 22 ``` | Flag | Coverage Δ | | |---|---|---| | Python | `97.74% <100.00%> (+0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files Changed](https://app.codecov.io/gh/abess-team/abess/pull/516?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team) | Coverage Δ | | |---|---|---| | [python/abess/bess\_base.py](https://app.codecov.io/gh/abess-team/abess/pull/516?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=abess-team#diff-cHl0aG9uL2FiZXNzL2Jlc3NfYmFzZS5weQ==) | `98.90% <100.00%> (+0.02%)` | :arrow_up: |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[Mamba413]

Thanks! I think this is fine, and we can merge it.

[bbayukari]

R API has been updated in 96ed869f48a0ba954b1ef101616dbf12ae7cbd3a.