Rewrite UI updates on webview events

Use mutation observer to toggle save button visibility
Use mutation observer to sync search-input and search-tag
Optimize application startup
Fix uri loading when app already open

Optimize link handling on click

Open external links in browser on left click
Prevent opening links in browser if not clicked by user

Rewrite webview interaction implementation

Use webkit.postMessage to exchange messages between app and webview
Fix offline issue on application start-up without connection

Optimizations and theme switch fix

Fix theme switch for latest devdocs version
Replace $ with document.querySelector
Remove old settings migration

Bug fixes and optimizations

Fix single documentation search keyboard interaction
Show documentation tag when started from tty
Optimize documentation tag visibility
Various code optimizations

Single Documentation Search

Add support for single documentation searching
Add auto switching to dark/light GTK theme
Sync keyboard shortcuts/behavior with browser version
Fix error when no network available (enable web app cache)
Add shortcuts for zoom in/out/reset

Add single instance support

add dbus service for single app instance

fixes ssue #8

Add Finder, Fix Theme Bugs

Add finder with Ctrl+F shortcut
Fix theme change and unstyled application bugs

Update to Webkit2

offline is now working
optimized application code

Fix compatibility with new UI

Add preferences menu item
Remove menu select docs, toggle layout and toggle light buttons