travis: add SCons timings, fix comment in Makefile

.travis.yml

@@ -99,7 +99,7 @@ script:
    else
      ./configure BENCHMARK=${BENCH};
    fi
- - make
+ - SCONSFLAGS='--debug=time' make
  - make test || TEST_RESULT=$?
  - if [[ ${COVERAGE} == true ]]; then
      ./mason_packages/.link/bin/cpp-coveralls --build-root . --gcov-options '\-lp' --exclude mason_packages --exclude .sconf_temp --exclude benchmark --exclude deps --exclude scons --exclude test --exclude demo --exclude docs --exclude fonts --exclude utils > /dev/null; 

Makefile

@@ -41,7 +41,7 @@ python:
 	python bindings/python/test/visual.py -q
 
 src/json/libmapnik-json.a:
-	# we first build memory intensive files with -j1
+	# we first build memory intensive files with -j$(HEAVY_JOBS)
 	$(PYTHON) scons/scons.py -j$(HEAVY_JOBS) \
 		--config=cache --implicit-cache --max-drift=1 \
 		src/renderer_common/render_group_symbolizer.os \