Test fails on 32-bit

[AdamWill]

Similar to core, one of the trajectory tests fails on 32-bit compile (with GCC 5.1.1):

15: /builddir/build/BUILD/roboptim-trajectory-3.1/tests/cubic-b-spline-matplotlib.cc(113): error in "trajectory_cubic_b_spline_matplotlib": check output->match_pattern () failed. Mismatch at position 8040

Full build log is available for now (will expire in a few weeks).

[bchretien]

This looks like numerical errors in the stdout files, e.g.:

# 1st derivative:
# [2](0,0)
# [2](28.125,-3.125)
# [2](3.10862e-13,3.10862e-13)

vs

# 1st derivative:
# [2](0,0)
# [2](28.125,-3.125)
# [2](0,0)

We can normalize values close to 0 before printing to avoid this problem. Since we're not printing with a great precision, the nonzero values should be ok. Also, the Fedora build logs contain all the output, so these errors should be easy to track down.