Add ability to edit feed name, closes #319
Update translations
Fix code tags overflowing container, closes #315
Style stories marked as "keep unread"

Adds styling to stories marked as "keep unread", so they can be distinguished
from never-read stories.

Fixes #210.
Merge pull request #323 from Koronen/style-keep-unread-stories

Style stories marked as "keep unread"
Enable gzip compression when parsing feeds, closes #324
Add support for Heroku button; move docs around a bit
Add new translations
app.json: use main repository URL for logo
Merge pull request #326 from InPermutation/master

app.json: Add "repository" metadata
svg badges using shield.io
Merge pull request #327 from InPermutation/svg-badges

svg badges
Change FetchFeed consturctor to use named parameters

This way you can initialize the FetchFeed class with passing a custom
logger, but without having to pass a parser.
Update translations
Add integration test for feed importing

Covers:
- Initial import
- Update where no new entries are available
- Update where new entries are available
Add integration test for feed with invalid pub dates
Change feed importer to use story ids to determine if a story is new

This should make feed importing more robust. Pub dates of feeds and
articles can not always be trusted (see
https://github.com/swanson/stringer/issues/261).
Using this mechanism we should always reliably be able to tell which stories
are new, regardless of pub dates being correctly reported or not.
Adhere to project code style (string double quotes)
Support feeds with stories with scheme-less urls

Example is https://blog.golang.org/feed.atom.
Urls in this feed are referenced to as scheme-less urls
(//blog.golang.org/context).

This commit adds normalization of story urls using the feed url. If a
story url doesn't have a scheme it will use the scheme of feed's url.
Refactor url normalization in StoryRepository