travis.yml: installing dependencies should be in 'install' key
travis.yml: adding 'npm install' to install key

It was there by default, but we overrided it in previous commit.
Refactor isTestPackage method.
Fixes issue https://github.com/amber-smalltalk/amber/issues/1017
Move methods isTestXXX to SUnit package
Merge pull request #1019 from rcsimm/master

Refactor isTestPackage method.
API-CHANGES: isTestXxx
CHANGELOG: Helios SUnit Runner