Deprecate ulex in favor of ulex-campl5

[XVilka]

Because original ulex is abandoned, will never be updated it seems, and will not build with OCaml 4.08, because it depends on campl4, which is not supporting 4.08 either. Moreover, seems that ulex-campl5 is a drop-in replacement for ulex, so shouldn't cause any issues.

See ulex original repository, and ulex-campl5 fork.

[pmetzger]

What still depends on ulex?

[XVilka]

@pmetzger: piqi and piqilib, I am working on making BAP work on OCaml 4.08, and those are dependencies. I am also expecting when 4.08 support will be merged in Camlp5. Seems no response, sigh.

[XVilka]

See the whole list at opam site:

    beluga
    ccss<1.6
    cduce
    cow<2.0.0
    frenetic>=3.2.0 & <5.0.0
    fstar>=0.9.5.0
    higlo
    kremlin
    lambdoc
    mezzo
    opa-base
    piqi<0.7.0
    piqilib
    pxp
    rdf>=0.5 & <0.10.0
    sociaml-vcard
    wdialog

[XVilka]

Focusing on porting to sedlex instead.