Allow numeric operators such as >, >=, <, <=

[Moreno-Gentili]

For numeric values, such as HTTP status codes, I would like to filter them by using the greater than and less than operators.

statusCode >= 400 and statusCode < 500

However, this is currently not possible since the only operators allowed are:

property-name [ = | != | like | not like ] search-term

[alaatm]

My time is very limited to work on any new features on this project. However, pull requests are always welcome.