Merge branch 'release/2.4.18' into develop
version for snapshot
Testcase to reproduce PROB-295
Added AF, EG to CTL parser
Added a new LTL operator ('Av(x)' for CSP specifications only).
Changed the available operator's arity.
Fixed parsing of 'available' and added a test case.
set release version
Merge branch 'release/2.4.19'