Replicated the class PHUIPagerView.php to implement a [Prev][Next] pager
with fixed pageSize=1 and surroundingPages=0.
I had to work around the fact that in Phriction the last version of a Document
can also be referenced as v=0.
This caused the pager to diplay the [Next] button with a link to version=1
when viewing the last version of a wiki Document.
Future improvements:
Currently, the first version of a Document displays the [Prev] button with a link
to the last version. I haven't found any elegant workaround to this behaviour, so I
have left it untouched.
This also causes wiki Documents with only 1 version to display the [Prev] button linked
to itself.