upload config files on publish; version bump
Suppress nav links in previews

[Delivers #66700278]
Merge branch 'master' into 66700278-preview
Add back old preview method

[#66700278]
Detect missing preview ranges

[#66700278]
Fix PDF preview

[#66700278]
Add GhostScript

[#66700278]
Include ALL THE SETTINGS

[Delivers #67956640]
Add zip dependency
Add zip dependency

[Delivers #68026716]
Bump polytexnic dependency
Merge branch 'polish' of https://github.com/softcover/softcover into polish
Change EpubCheck to use a bin directory

[Delivers #67505774]
Handle empty chapters gracefully

[Delivers #67506354]
Merge branch 'store_config' into polish

Conflicts:
	lib/softcover/version.rb
Issue pull request for branch polish

[Delivers #67506354](https://www.pivotaltracker.com/story/show/67506354)
[Delivers #67505774](https://www.pivotaltracker.com/story/show/67505774)
[Delivers #68026716](https://www.pivotaltracker.com/story/show/68026716)
[Delivers #67956640](https://www.pivotaltracker.com/story/show/67956640)
[Delivers #66700278](https://www.pivotaltracker.com/story/show/66700278)
[Delivers #66668518](https://www.pivotaltracker.com/story/show/66668518)
[Delivers #62686770](https://www.pivotaltracker.com/story/show/62686770)
[Delivers #66028938](https://www.pivotaltracker.com/story/show/66028938)
[Delivers #66027166](https://www.pivotaltracker.com/story/show/66027166)
[Delivers #66024284](https://www.pivotaltracker.com/story/show/66024284)
[Delivers #65817046](https://www.pivotaltracker.com/story/show/65817046)
[Delivers #65825676](https://www.pivotaltracker.com/story/show/65825676)
[Delivers #62899518](https://www.pivotaltracker.com/story/show/62899518)
[Delivers #63658440](https://www.pivotaltracker.com/story/show/63658440)
[Delivers #65583588](https://www.pivotaltracker.com/story/show/65583588)
[Delivers #65068506](https://www.pivotaltracker.com/story/show/65068506)
[Delivers #61781888](https://www.pivotaltracker.com/story/show/61781888)
[Delivers #65336996](https://www.pivotaltracker.com/story/show/65336996)
[Delivers #62882672](https://www.pivotaltracker.com/story/show/62882672)
[Delivers #63332572](https://www.pivotaltracker.com/story/show/63332572)
[Delivers #63337610](https://www.pivotaltracker.com/story/show/63337610)
Merge pull request #97 from softcover/polish

Polish