Fix retrieval from non-default repositories

Since the `<remoterepo>` tag is not in the scope of the `<resolve>`
target, fetching artifacts from repositories different from Maven
Central fails (e.g. JAI).

Backport fix for bz-63438 to 1.9.x

Backported from 1.10.x: dfeee59cca

Resolver Ant tasks instead (https://maven.apache.org/resolver-ant-tasks/)

This closes #186 pull request at github/apache/ant repo.

thanks @twogee

Update selectors.html

Correct small typo in selectors.html