build.xml files reject Ant 1.8

```
What steps will reproduce the problem?
1. Install Ant 1.8
2. Run an Ant task from a hackystat project
3. Rejected, saying require 1.7.1 or later...

When looking into build.xml, it actually only accept 1.7.X except 1.7.0.
There actually only one version (1.7.1) satisfy this.


```

Original issue reported on code.google.com by `zsxking` on 29 Jan 2010 at 8:35
