Support :-abp-*() syntax

[theseanl]

ABP is introducing backward-compatible syntaxes [-abp-has and [-abp-has-text.
https://issues.adblockplus.org/ticket/3143
https://issues.adblockplus.org/ticket/5249
We need to convert them into :has and :contains respectively.

[ameshkov]

-abp should be just an alias for our existing -ext

[ameshkov]

@seanl-adg I've been thinking about it lately and after all, I suppose we should support this syntax natively (talking about :-abp-has()).

It's not hard to do, and it'd be easier for people to import external filter lists which use that syntax.

Here is what should be done:

1. Support :-abp-has() as a synonym to has
2. Release an updated 1.0.8 version
3. Update product-specific issues about upgrading ExtCss -- add information about parsing #?# and :-abp-has

[theseanl]

They changed their syntax to -abp-contains instead of -abp-has-text