Add missing groupIds in pom files

Missing groupId cause the tycho-set-version plugin to fail with an NPE,
see https://dev.eclipse.org/mhonarc/lists/tycho-user/msg04571.html
(cherry picked from commit 2127604a31932b60bef9ce4335a21b8fcf18c0da)
Bump Tycho version number to 0.19.0
(cherry picked from commit cbec3e6fb263eedcda3311a72190ac96ad463cb8)
Combines toolbar menu structures

The "show inferred semicolons" action was placed in its own menu
structure, whereas other actions are combined under a different menu
structure. This commit merges both of them.

For this to happen the deprecated usage of an Eclipse action in the show
inferred semicolons action is replaced with the newer handler
architecture.

This also moves the command for toggle mark occurrences to a different
location in the pom.xml.

Furthermore, a preference to toggle the "show inferred semicolons"
action is added to the editor preference page.

This does not introduce functional changes to the logic of the
"show inferred semicolons" action.

Fixes #1002042
Helper script to bump the version number.

This script automates up to a point, but some updates need to be done
manually:

- <parent> tags that refer to the root pom.xml (without a relative path)
- features.xml files that get auto-generated based on templates in resources/
Merge pull request #643 from dragos/improvement/set-versions

Make bump-version a simple(r) operation
Merge pull request #646 from sschaef/t1002042-merge-menu-structure

Combines toolbar menu structures