correct makefile documentation (within the makefile). We no longer ne…

…ed python2 for cpplint

makefile

@@ -47,11 +47,7 @@ help:
 	@echo '      * mix -> {rev, fwd, prim}'
 	@echo ''
 	@echo '  Cpplint'
-	@echo '  - cpplint       : runs cpplint.py on source files. requires python 2.7.'
-	@echo '                    cpplint is called using the CPPLINT variable:'
-	@echo '                      CPPLINT = $(CPPLINT)'
-	@echo '                    To set the version of python 2, set the PYTHON2 variable:'
-	@echo '                      PYTHON2 = $(PYTHON2)'
+	@echo '  - cpplint       : runs cpplint on source files.'
 	@echo ''
 	@echo ' Clang Tidy'
 	@echo ' - clang-tidy     : runs the clang-tidy makefile over the test suite.'