message: docker-compose.yaml: Default to empty build type
  Allow targets to specify a CMake build type but do not set a default
  (removed 'Release').  The CXX flags for Release slow the builds down
  significantly on Travis-CI (which can hit the time limit for jobs).
diff: @@ -16,7 +16,7 @@ services:
  - BUILDCORDOVA=${BUILDCORDOVA:-OFF}
  - BUILDSWIGNODE=${BUILDSWIGNODE:-OFF}
  - BUILDEXAMPLES=${BUILDEXAMPLES:-OFF}
  - - CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE:-Release}
  + - CMAKE_BUILD_TYPE
  - IPK=${IPK:-OFF}
  - RPM=${RPM:-OFF}
  - NPM=${NPM:-OFF}
  