Add hash for settings below, to check if they change in runtime

Done ✅:

```
colorScales: defaultColorScales, // -> hash FNV-1a
clippingOptions: undefined, // -> hash FNV-1a (#225)
```

Todo:

```
domainOptions: defaultDomainOptions,
variableOptions: defaultVariableOptions,
parseUrlCallback: parseOmUrl, 
postReadCallback: undefined,
```