Greedy regular expression causing components to be ignored by Nokogiri; Additional vars passed into rake task

A few things here:

1) I added the ability to pass in  a custom component and the simple param to the rake task too

2) There was a bug I discovered because we had some messily formatted EAD XMLs. They are properly formatted EAD XML, but the `<eadheader>` started on the same line as as the root `<ead>` element and so in behaviors.rb SolrEad::Behaviors.components#10 when the default xmlns is stripped it greedily deleted the rest of the line. Then when Nokogiri parses it, it attempts to tidy up the now improperly formatted xml and cuts off at the `</eadheader>`. 

FIX: I made the regex lazy and added a test.

3) Updated the documentation to reflect the rake changes I made.