Exposes format command.
Moves standard Dari checkstyle config to be available everywhere via verify phase and fixes all checkstyle issues.
Adds Clirr to automatically check for backward compatibility.
Moves enhance-classes configuration to be more specific to its execution instead of as global options to the exec-maven-plugin.
Fixes checkstyle and clirr to actually run during the build process.
Moves the clirr and checkstyle stuff into a profile so that it doesn't run by default on all projects.
Merge branch 'master' into feature/solr-range-facet

Conflicts:
	db/src/main/java/com/psddev/dari/db/SolrPaginatedResult.java
Fixes compile errors caused by previous merge.
Formatting.