Break down plot_demo_plotting.py in two smaller examples

plot_demo_more_plotting.py contains the most advanced usages of plotting
Fix broken links related to plotting documentation
Merge pull request #327 from lesteve/break-down-plotting-examples

Break down plotting example
DOC: use link rather than manually updated list of functions
DOC: missing dot in README.rst
DOC: remove stray 'n'
reorder_img was modifying the input image affine

fixes #325
Merge branch 'enforce3Dargs' of https://github.com/banilo/nilearn into enforce3Dargs
additional change to regexp