Commits for Zengine

#144715: Adding INSTALL and README. Big thanks to Chris Herberte for the install and magdelaine for the readme info from her docs wiki on g.d.o.

CSS cleanup

this commit:
- fixes #167387
- adds background images for rollover block/node edit links
- moves css file handling into a separate function
- creates hook_zengine_css to allow other modules to add/alter css files

Added "edit" link to nodes within a listing. Also moved block and node edit links into an array available to the templates.