Improve syntax highlighting styles (#1450)
* Cleanup syntax highlighting styles
* Replace hardcoded color values with [base16](http://chriskempson.com/projects/base16/) Sass variables
* Harmonize padding between GFM code blocks and `{% highlight %}` code blocks
* Improve readability of line numbers
* Add longer code block example to test double digit line numbers
* Adjust code block colors for specific skins
Add Prettier ignore file
Stop prettier from messing with Markdown files.
Update CHANGELOG and history
Minimize JSON data (#1449)
* Remove Lunr trimmer & bring back colons
* Add Greek Stemmer
* Translate search_placeholder_text and results_found to Greek
* Minimize JSON data
* Truncate Words
* Move store variable into a new file
* Move Lunr files into a new folder
* Add defer to lunr scripts
* Add search_full_content switch
Update CHANGELOG and history
Upgrade Font Awesome to version 5 (#1446)
Upgrade Font Awesome to version 5 (SVG with JavaScript)
Close #1396
Update CHANGELOG and history
Fix stuck sidebar when resizing viewport
Close #1447
Update CHANGELOG and history
Add lunr-gr.js and fix lunr-en.js (#1445)
* Remove Lunr trimmer & bring back colons
* Add Greek Stemmer
* Translate `search_placeholder_text` and `results_found` to Greek
Update CHANGELOG and history
Round top right corner of code block icon
Reduce visual weight of code blocks
Flatten shadow and remove borders relying on background color to highlight code.
Update CHANGELOG and history
Fix line number width in code blocks
Code blocks with short line widths can cause `td.gutter` width to stretch, adding in undesired white space.
Declaring widths on the table's columns fixes #1437
Add `{% highlight linenos %}` examples to test and demo sites.