debug/release: Add minimal debug/release CI builds

This commit enables both a minimal DEBUG and minimal RELEASE build on
Travis-CI.

Signed-off-by: Noel Eck <noel.eck@intel.com>

docker-compose.yaml

@@ -16,6 +16,7 @@ services:
       - BUILDCORDOVA=${BUILDCORDOVA:-OFF}
       - BUILDSWIGNODE=${BUILDSWIGNODE:-OFF}
       - BUILDEXAMPLES=${BUILDEXAMPLES:-OFF}
+      - CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE:-Release}
       - IPK=${IPK:-OFF}
       - RPM=${RPM:-OFF}
       - NPM=${NPM:-OFF}