Adding ws-cleanup plugin.
Jobs need to be sorted in a view, or Jenkins will ignore them.

Adding missing jobFilters element, which was throwing false positive on the diff between current and wanted.
Fix to prevent unnecessary updating of views.

Apparently there is a bug where trailing whitespace in the raw XML input (i.e. before REXML::Document object has parsed it) adds a single space character after the XML declaration (`<?xml … ?>`), which was causing the `current.string == wanted.string` to return false even when the contents of the XML. Adding `rstrip` to both the current and wanted configs appears to resolve this.

Adding `require 'rexml/document` although not strictly necessary here.
Version bump to v0.2.11