Merge pull request #149 from pmuir/140

Misc fixes for spider.rb
Merge pull request #155 from pmuir/remove_redundant_code

Improve perf by removing a loop that does IO
Add support for reading from sitemap.xml
Merge pull request #152 from pmuir/sitemap_xml

Add support for reading from sitemap.xml
Display paths properly in gallery

* use __ rather than _ as the ‘dummy’ separator char,
  as it is much less commonly used than _ in a
  file/directory name
* replace __ with / when displaying paths in the gallery