RF - Make peaks_from_model part of dipy.direction
DOC: Warn about the GPL license of SHORE.
DOC: Replicate this in the docstring, just to be safe.
TST: Test for both data with and w/0 b0.
BF - older C compilers do not have round in math.h, uisng dpy_math instead
BF: define our own round for c++98 compatibility
BF: round to nearest even
BF: use define and use dpy_signbit instead of signbit. Use dpy_rint instead of round.
BF: use npy_* functions directly instead of defining our own dpy_* versions
Use NPY_PI instead of DPY_PI
BF: fixed float overflow issue
Minor typo
Merge pull request #494 from omarocegueda/fix_round

Fix round
Merge pull request #504 from Garyfallidis/bf_float_overflow

Bug fix float overflow in estimate_sigma
BF - use different sort method to avoid mergsort for older numpy.
Merge pull request #507 from MrBago/bf_numpy_mergesort

BF - use different sort method to avoid mergsort for older numpy.
Merge pull request #501 from arokem/dti-test-nob0

TST: Test for both data with and w/0 b0.
Merge pull request #491 from MrBago/mv_peaks_from_model

RF - Make peaks_from_model part of dipy.direction
Merge pull request #499 from arokem/shore-license

DOC: Warn about the GPL license of SHORE.
Merge branch 'nipy-dipy-master' into add_tests_resample