* Improve the .pom file installed when using --enable-maven-install.
* Ignore some new, removed, or awkward methods in Glom 1.21/22.
This allows us to build with both Glom 1.20 and Glom 1.21/22,
though there is currently no check for Glom 1.22, which installs
in parallel.
(Murray Cumming)