Box Sync

What's new in this version:

Fixes:
- When re-authenticating existing from Preferences > Accounts, Mailspring no longer gets stuck displaying the settings window in some scenarios
- Fixes an occasional issue that could cause the people sidebar to become blank if the user's LinkedIn handle was malformed
- A new button in Preferences > Accounts allows you to quickly retrieve + copy the last ~50 lines of your sync logs, making it much easier to collect information we need for debugging.
- Google Calendar and Contact sync are much more reliable thanks to improved handling of Google expiring People "sync tokens"
- When applying templates in the composer, Mailspring correctly clears the styling of the first line of your draft
- When switching signatures in the composer, Mailspring no longer mangles your draft content in some scenarios
- In the composer, Select-all + Delete no longer fails to delete your text if the very last block of your message is your signature
- In the composer, undoing past the end of your "undo history" no longer removes focus from the editor
- Mailspring now autolinks URLs that contain multiple ? in the query string correctly
- Mailspring uses relative URLs for it's own assets, so the filesystem path to the application can safely contain characters like # and ? safely
- When messages must scroll horizontally, we add 20px to the computed height to account for the scrollbar and avoid clipping the last line of text