Filters don't work when searched value contains:

1. {some_text}<
2. {some_text}>
3. {some_text},{some_text}
4. {some_text}|
5. {some_text}.
6. <>
7. ,
8. =
9. and in other cases with special characters

In some case it throws error "The binary operator GreaterThan/Less than is not defined" or "{some_text} not found" and in other cases just returns all data.

I investigate this and found out that the issue with <>= characters is in regexp for filterSplits here:
https://github.com/Biarity/Sieve/blob/master/Sieve/Models/FilterTerm.cs#L36
Special characters considered as Operators in this case.

Also, issue with comma is in regexp for filters:
https://github.com/Biarity/Sieve/blob/master/Sieve/Models/SieveModel.cs#L35

These fixes require a lot of improvements in the library logic, and it will be great if you add support for special characters.

Thanks in advance!