Use Reader.

To avoid to pass opts explicitly around (as we
do not use it very much at the moment anyway)
HLint suggestions.
Move more things to Reader.
Little restructuralization.
Merge pull request #1399 from xkollar/reader

Modad.Reader + HLint for MediaWiki writer
MediaWiki writer: Minor renaming of 'st' prefixed names.
Abstract usefull functionality.
HLint
Move handy function into Shared module.
Added TracWiki writer.
Fix me!
Fix me!
Fix me hlint
Some examples
Fix me!
Typo