RFE: General categories cleanup

[cooljeanius (Eric Gallager)]

This was inspired by revisiting ticket #37832 after seeing cal's commit r102355 in irc. The following categories only have a single port in them:

​mercurial: currently only contains hg-forest, could also possibly contain mercurial, py*hgsvn, py*mercurial_keyring, py*hggit, py27-hgsubversion, and tortoisehg

​win32: currently only contains nsis, could also possibly contain ASFRecorder, i386-mingw32*, icoconvert, mystonline-wine, octave-windows, ophcrack, p5*parse-win32registry, pev, png2ico, rdesktop*, wine*, and wxmsw

​wsn: currently only contains nesc, not sure what else it could contain

​squeak: currently only contains squeak, pretty sure that's the only thing it could contain

​lua: currently only used for luash, could also be used for lpeg, lua*, ocaml-lua, prosody, swig-lua, texlive-luatex, toluapp, and wxLua

​ipv6: currently only used for aiccu, could also be used for a lot of other things

​html: currently only used for xml2, could be used for so many other things that it might not be worth it

​emacs: currently only used for po-mode.el, could also be used for auctex, cedet, *.el, ecb, emacs*, erc, ess, jove, lookup, magit, mg, nxml-mode, org-mode*, ProofGeneral, psgml, py*pymacs, slime, tex-whizzytex, vile, xemacs, and zile

Also the "​database" and "​databases" categories should probably be combined with one another. Same thing with the "​ml" and "​ocaml" categories.

(Note: All "*"s in the above are wildcards)

[cooljeanius (Eric Gallager)]

oops forgot to set this to "enhancement" instead of "defect"

Edit: I probably should have cc-ed cal, too, since I mentioned him in the OP

[seanfarley (Sean Farley)]

I'm working on the mercurial ones as we speak.

[seanfarley (Sean Farley)]

Up next (hopefully later today) will be the emacs ones.

[cooljeanius (Eric Gallager)]

Thanks sean!

[larryv (Lawrence Velázquez)]

Please remember to obtain permission before changing ports that are not {no,open}maintainer.