ISIS-980 Do not render empty sub-menu sections in the tertiary actions menu panel

Show the divider only if there are custom sub menu items
ISIS-928: ignoring utility shell script (add to .gitignore).
ISIS-928: minor updates to todoapp and simpleapp (doc changes, tiny bug fix)
ISIS-981: if no security manager is configured (specifically this means, if running in the fixtures during bootstrapping) then ALLOW the interaction, rather than VETO it as previously.
ISIS-981: reordering import statements is all.
ISIS-284: enhancing ServicesInstaller so can be used within mvn metamodel (basically: a flag to optionally ignore any services that cannot be instantiated); also fixes to IsisMetaModel to correctly set up the MetaModelValidator (composite).
ISIS-284: various fixes and enhancements to ValidateMojo; removing builder for IsisMetaModel; also attempt to exclude dependency on old google-collections.