Frontend-GNOME: guard ChatTreeView's cell renderer with null checks
Engine: allow space and no separator in DSA message pattern
Engine(-Tests): fixed URL detection which contain ' (closes: #983)
Engine(-Tests): allow upper-case characters in heuristic URLs (closes GH-182)
Merge branch 'stable'
Engine-IRC: show channel mode changes (again)

This fixes a regression introduced in e15c98a19223fac928690259eb98db7eebd928af
Travis-CI: don't sign changes file neither the source package
Frontend-GNOME: implemented message counter