fixed error withimplicit operation in prob + missing state existens check

f(s:set of nat)n:nat
post r in set s
Change ide/platform/pom.xml to allow command-line skipping of the
git-commit-id plugin and update the version in use to 2.1.8
Update travis config to skip git-commit-id calculation and alter the
`script` command to be a yaml list
enabled model checking to be used for implicit function solving
updated the prob model checker to be able to solve implicit functions
Reduce the amount of javadoc noise
Change travis-ci config to (attempt to) quietly download all of the
maven plugin dependencies before 'mvn install' is executed to reduce the
size of the build log.
Merge branch 'origin/kel/astv2'

Conflicts:
	core/interpreter/src/main/java/org/overture/interpreter/values/FunctionValue.java
Merge branch 'origin/development'
changed profile for prob download and packing
corrected a wrong guard
Merge branch 'origin/kel/astv2'

Conflicts:
	ide/plugins/prob-runtime/linux.x86/pom.xml
	ide/plugins/prob-runtime/linux.x86_64/pom.xml
	ide/plugins/prob-runtime/win32.win32/pom.xml