Great big revampage: no more strings anywhere. It's all ColumnExps all the way

down (well, all the way to the public API anyway).

Revamped index creation while I was in there because that was one of the big
string users. Now you just put @Index on the field you want indexed, and if you
want a multi-column index you do things with a magical static method just like
we do for complex (function) indices.

@UniqueConstraint may still go away since it's basically exactly the same thing
as @Index(unique=true), so it's kind of pointless to support both.

etc/libs-incl.xml

@@ -3,6 +3,7 @@
 <project name="library-dependencies">
   <fileset dir="${libs.dir}" id="depot.libs">
     <include name="ant.jar"/>
+    <include name="commons-collections.jar"/>
     <include name="ehcache.jar"/>
     <include name="google-collect.jar"/>
     <include name="junit4.jar"/>