Better docs for theming

[seanh]

Our current docs for writing themes aren't very useful. They could do with being rewritten, possibly with a structure along these lines:

• Overview (introduce key concepts)
• Tutorial (step-by-step tutorial for developing an example theme, using a real working example, no assumed knowledge, no steps missing)
• Troubleshooting
• Best practices
• Reference

[tobes]

#1026 is related to this should they be combined

[seanh]

As in #1026, this issue should also include better docs for customizing the CSS, including that you should make CSS changes in ckan/public/base/less/custom.css to keep them separate from CKAN's CSS, compile LESS to CSS using ckan/bin/less and ckan/bin/less -p, and then minify with paster front-end-build.

[tobes]

paster front-end-build should do the css building as part of it's work

[seanh]

Work on this has started here: #1223 Closing this issue as a duplicate