run all tests with npm test
run all tests with npm test

node tests were moved out of the test directory in 91bb2f5c which
meant mocha no longer ran then during `npm test`. Therefore, the
command line arguments to mocha have been updated to ensure that
all tests now run.

FSMaxB/mathjs,josdejong/mathjs,FSMaxB/mathjs,FSMaxB/mathjs,josdejong/mathjs,FSMaxB/mathjs,josdejong/mathjs,josdejong/mathjs,josdejong/mathjs,FSMaxB/mathjs