Updated astropy-helpers to v0.4.2
Merge pull request #46 from astrofrog/update-helpers

Updated astropy-helpers to v0.4.2
Initial implementation of speedup attempts, including parallel implementations.
C version of the reproject routine, including the parallel one.
Attempt at fixing the Travis failures related to documentation and Python 2 vs 3.
More Python 3 fixes.
Python 3.4 enforces K&R C style, account for that.
Temporarily enable the selection of the method and number of cores to use
from the high level routine.
New implementation that uses cython for setting up the arrays,
and raw C for the computation.
Revert "Temporarily enable the selection of the method and number of cores to use"

This reverts commit d3866211578d1a21b74dbd34a5f3831558cc4025.
Tentative workaround for the egg_info travis failures.
Fix the previous fix: don't import numpy at all for egg_info.
Move ilon/ilat/olon/olat inside the C function as local variables.
Move the declaration of the static arrays at the top of the function.
Merge branch 'parallel_repro' of github.com:bluescarni/reproject into parallel_repro