Added input_fns to CFProjection, allowing projection level transformations of input activity

Added a input_fns parameter to CFProjection and added code to apply them in the activate
methods of CFProjection and SparseCFProjection.
adjust docs formatting
Fixed non-qualified numpy imports in projection/__init__.py
Added missing _norm_total attribute in SharedWeightCF
Added support for loading old snapshots, before LISSOM moved
ReST and Sphinx-based website

This commit replaces the old PHP-based website with the new
ReStructuredText-based implementation. The actual website is to be
generated using Sphinx.
Makefile: Updated the `doc` target to reflect new website
Merge branch 'website' of github.com:ioam/topographica into website