Text.ParserCombinators.* is a bad name

[Donald Bruce Stewart]

* Firstly, a library naming issue. Text.ParserCombinators feels like a
clunkey name. This week I was working on a set of regex combinators,
that ideally would go under:

    Text.Combinators.Regex

but we're stuck with Text.ParserCombinators.Regex. Making me think that:

    Text.ParserCombinators.ReadP
    Text.ParserCombinators.Parsec
    Text.PrettyPrint.HughesPJ

namespace should be deprecated in favour of:

    Text.Combinators.ReadP
    Text.Combinators.Parsec
    Text.Combinators.HughesPJ

Reflecting the wide variety of text-manipulation combinators we use. 
The latter seem more elegant. Parsec in particular can lead to some 
noisy import statements in its current namespace.


* Secondly, an FAQ on #haskell is "Where is fst3/snd3/thd3?"

Lacking some fun generic system for hacking at tuples, perhaps 
fst3/snd3/thd3 should be put back into the base library under 
Data.Tuple, next to fst/snd?  I note they were in (at least some 
versions of) Haskel 1.2, and they're even defined locally in GHC.PArr.

I'll draft the patches if people think these are reasonable.

Cheers,
  Don