changed unit syntax
Merge pull request #459 from esc24/is_contiguous_tol

Added tolerances to Coord.is_contiguous()
Merge pull request #465 from cpelley/unit_syntax_chng

Improved unit syntax on cube.__str__.
Area weighted regridding.
More work on regridding.
Reworking coord copying.
More rework.
Fixed units conversion
Move to iris.experimental.regrid
Broken bounds wrapping
Use of axis keyword in average. This needs numpy v1.7.
Start of tests.
More testing.
More corner cases for cropping bounds.
More tests.
Support for regriding to scalars.
subsampling test helper
Pep8 tweaks.
Partial review.
Review actions.