[GHC] #974: Add unzipEithers, lefts, rights to Data.Either

[Neil Mitchell]

Hi

> http://www-users.cs.york.ac.uk/~ndm/temp/identifier_length.png
>
> Uses up the Y, length on the X.

Since roconnor asked, here is the raw data:

1	4
2	49
3	135
4	272
5	337
6	452
7	381
8	399
9	362
10	325
11	308
12	252
13	209
14	178
15	140
16	88
17	67
18	64
19	67
20	42
21	39
22	34
23	34
24	23
25	35
26	16
27	18
28	11
29	10
30	1
31	4
32	2
34	1

Thanks

Neil