Properly pretty-print typeclasses for REPL command ':doc'

This requires adding info about the parameters and instances to the
ClassDoc constructor of the Docs datatype.
Remove the REPL Info command

Removed from the `Command` datastructure, REPL-parser, REPL-help,
process and ideslaveProcess. The functionality of showing infos for
typeclasses has been subsumed by the `DocStr` command.
Remove deprecatd classInfo method from REPL.hs
Show defined and automatically generated class instances in different blocks
Display docstrings for typeclass parameters and simplify dispaly of subclasses

The docstrings for the typeclass parameters do not actually show up yet
because the structure is not populated.
Merge branch 'master' into fix/1047-repl-doc-for-typeclasses
Add myself to the CONTRIBUTORS file
Merge pull request #1155 from paulkoerbitz/fix/1047-repl-doc-for-typeclasses

Fix/1047 repl doc for typeclasses