caching prototype without invalidation
update readme
remember cache keys

… so we can purge it later
add cache invalidation
add contribution robustness
hook modules into cache invalidation
Merge branch 'template-caching' into release-1-10-14
add code doc to template caching
avoid a pointless query on nearly every page
cache feed discovery
skip some admin-code in fronted
cache bitlove widget
fix notice
Added Auphonic Credits to Donations
Forgot the Initial Service creation
explain caching in readme
mention cache deactivation in README
Merge pull request #442 from podlove/auphonic_credits

Added Auphonic Credits to Donations
mention auphonic credits in readme
slugify: use rawurlencode instead of urlencode

Rule of thumb is: use `rawurlencode` for everything _before_ the `?`
and `urlencode` for everything after. Since `slugify` is used for the
former, this change makes sense. However, the recommended usage is not
obvious from the method name, so … it would be great to find a more
clear solution at some point.

One notable difference is how spaces are handled:

```
$> rawurlencode(" ");
// '%20'
$> urlencode(" ");
// '+'
```