Build scripts exclude java 5+ functionality when build under java 6

Building grails under java 6 excludes java 5+ functionality, such as annotation support classes, because ant/build/compile.xml is performing the following check:

<equals arg1="$

" arg2="1.5"/>

Seems like this should be greater-than. This is an easy change to make locally but should be fixed in the distribution so that the posted java 6 binaries don't exclude these classes.