Switch to work with the feature/wip-switch-to-asset-pipeline branch
Refer to the precompiled application.css, which includes custom.css
Move images out of /public and into the asset pipeline

An oddity here is that I had to rename logo.png to
alaveteli-logo.png, or the version from the alaveteli
repository was used after precompiling the assets.
(This suggests that generation of precompiled assets
with "rake assets:precompile" is picking the wrong
version; i.e. not going through the asset path in
reverse order.)
Merge branch 'switch-to-asset-pipeline' into develop
No need to create or destroy symlinks now

Handled by asset pipeline.
Add .css suffix before .scss for consistency.

Doesn't seem to make any difference to preprocessing behaviour.
Restore logo.png

See discussion at https://github.com/mysociety/alavetelitheme/commit/0d2a72017779ba0cd7c7d40e0fa32713129333c5
Merge branch 'develop'