Add option to not salt cellular lookup

[astrsh]

Pull Request

Licensing

• [x] I am the original author of this code, and I am willing to release it under GPLv3.
• [ ] I am not the original author of this code, but it is in public domain or released under GPLv3 or a compatible license.

Goal of the PR

Allows lookup samplers to not be affected by the cellular sampler's salt

Affects of the PR

Only affects behavior if salting is explicitly turned off by setting salt-lookup to false

Types of changes

• [ ] Bug Fix
• [ ] Build system
• [ ] Documentation
• [x] New Feature
• [ ] Performance
• [ ] Refactoring
• [ ] Repository
• [ ] Revert
• [ ] Style
• [ ] Tests
• [ ] Translation

Compatiblity

• [ ] Breaking change
• [x] Non-Breaking change.

Contribution Guidelines.

• [x] I have read the CONTRIBUTING.md document in the root of the git repository.
• [x] My code follows the code style for this project.

Documentation

• [x] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

Testing

• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[duplexsystem]

I think it would be better to instead have an option for lookup salt where the default is the existing salt

[astrsh]

the lookup can be independently salted like any other sampler, eg:

type: CELLULAR
return: NoiseLookup
salt: 3
salt-lookup: true # default
lookup:
  type: OPEN_SIMPLEX_2 # Is actually salted as 3 + 6
  salt: 6

type: CELLULAR
return: NoiseLookup
salt: 3
salt-lookup: false
lookup:
  type: OPEN_SIMPLEX_2 # Is salted as 6
  salt: 6

[duplexsystem]

hmm ok

[duplexsystem]

@dfsek are you against merging this?