Added haskell-hayoo-url as a custom variable

[tonyday567]

It looked like the hard-coded url was being redirected to a new url, and went with the new one as the default. Added url-hexify-string to query.

[gracjan]

I'm a bit lost, does this pull request work together with #511 or instead of #511?

[tonyday567]

@gracjan, it's completely independent to #511. I just saw that the hayoo url was hardcoded and thought I may as well generalise it the same way as the hoogle edit.

[gracjan]

I see. Someday we need to generalize hayoo and hoogle handling as the code looks very similar for both.

[tonyday567]

@gracjan,, yes, or rationalise the hayoo and hoogle libraries even ;)

[gracjan]

and by 'rationalize' you mean...?

[tonyday567]

I meant that they do the same thing, and thus it would be beneficial to users of both libraries to work towards a common API, and perhaps look at commonalities in code. Just my idle opinion.

[gracjan]

Do you see obvious commonalities in code? You have changed that part of the code recently, is there something obvious that you could also improve before you forget?

[tonyday567]

No, nothing comes to mind.