Follow File Name Conventions

File naming conventions now state that all PHP files (except templates) should
be lower-case and use underscores to separate words in a filename.

includes/IslandoraTuque.inc, and includes/IslandoraTuqueWrapper.inc are not
included in this commit as there is another pull request that corrects their
names in place, and we would like to avoid merge conflicts.

islandora.info

@@ -6,8 +6,8 @@ core = 7.x
 configure = admin/islandora/configure
 stylesheets[all][] = css/islandora.base.css
 stylesheets[all][] = css/islandora.theme.css
-files[] = includes/MimeDetect.inc
+files[] = includes/mime_detect.inc
-files[] = includes/DublinCore.inc
+files[] = includes/dublin_core.inc
 files[] = includes/IslandoraTuque.inc
 files[] = includes/IslandoraTuqueWrapper.inc
 files[] = tests/islandora_web_test_case.inc