[3.1.0] Move schema files to schema/ directory, this is in preparation for mass-class rename

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1575 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/ConfigSchema/schema/URI.DefinitionID.txt

@@ -0,0 +1,11 @@
+URI.DefinitionID
+TYPE: string/null
+VERSION: 2.1.0
+DEFAULT: NULL
+--DESCRIPTION--
+
+<p>
+    Unique identifier for a custom-built URI definition. If you  want
+    to add custom URIFilters, you must specify this value.
+</p>
+