Add optional parameter to like(), or_like(), not_like() and or_not_like() methods.

[nalakapws]

This PR address the 2nd feature request from this #5641 issue.

[narfbg]

This is parameter creep ... It may look inconsistent, but a better option would be to just have having_like(), having_not_like(), etc.

And you must follow the styleguide.

[narfbg]

You're still ignoring the styleguide ...

[nalakapws]

Is there anything I have to do in order to make this PR get merged?

[narfbg]

Yes, there are still some spaces left in on lines 1100, 1171 (shown in diff with darker green).

And there's more significant stuff code-wise, but it will probably result in a lot of back and forth if I asked you to do all of it, so I can make those changes myself after merging. It's decent enough as it is, I just want less repetition.

[narfbg]

Yes, all of CodeIgniter doesn't match PSR-2 rules. We have our own styleguide, referenced in the contributing guide, which you should read before reviewing others' work.