Fixed imports and classes following holoviews refactor
Further fixes for switch to holoviews
Fixed Tutorials
Updated and fixed submodule references
Suppress bogus Numpy 1.7 API deprecation warnings from weave; fixes #559
Updated submodule reference
Added holoviews submodule reference
Merge branch 'master' into holoviews_refactor

Conflicts:
	.gitmodules
	external/holoviews
Merge pull request #602 from ioam/holoviews_refactor

Updated Topographica to use holoviews instead of dataviews