Fix reported crash edbbaa4

Update authorization using Github OAuth2 Web application flow.
Multi account support.
Notification support.
Printing support for codes and commits.
Support "Search code".
UI/UX improvements.
Bug fixes.

Fix reported crash caused by NPE 8d7777a

Fix trending issues.
Improve markdown rendering.
Fix issue filtering.
UI/UX improvements.
Various bug fixes.

Filter out pull request from issue listing.
Fix reported crashes

Minor bug fix on the previous release (v4.0.1) for issue #322

Fix reported issues from Play store review and Github:

• open binary and large file (>1MB) in external app. #322
• fix some repos does not load correctly. #316

UI/UX improvements.
New main view and navigation drawer.
Trending repo is back.
Bug fixes.

Fixed:

• Extreme memory pressure in GB
• Header coloring not working in GB
• Search spinner popup color on pre-L
• Scroll position getting lost when loading more data in a paged list
• Issue/PR header growing too large

Material theme