Fixed ref to old scitools.org page.
Merge pull request #441 from pp-mo/scitools_pagefix

Fixed ref to old scitools.org page.
Merge pull request #440 from pp-mo/test_arrays_reltol

Added iris.tests.assertArrayAllClose
Merge remote branch 'upstream/master' into esmf_conserve
tidy tests slightly
Attempt to add masking - calculation not right?
Check masks in test_missing_data (calc OK after all).
Fix endpoint bug in _make_test_cube
Rationalise testcases for debug output