* Changed the path from 'lastmodified' to 'last-modified' for consistency

* Moved theme-switcher code to scripts partial file
+ Add author's MIT license to featherlight javascript

Source: https://github.com/Still34/DocFx.Plugin.LastModified
Licensed under MIT License

+ DocFX by default ships with an older version of jQuery, switching to a newer version confuses parts of the DocFX Javascript.

+ Increase line-height to make pages look less squished.
+ Add master stylesheet.
	- Move content that are not theme-specific to master CSS.
+ Target latest featherlight.js instead of 1.7.6.
+ Add javascript for cornerifying images.
+ Add escape mention image, courtesy of @Andrewww1.

+ Stylized option menu
+ The menu now defaults to whatever theme being the most preferred one

+ Changes dark theme changes to a different css to respect future docfx.css changes
+ Merge featherlight plugin into the dark theme

+ Fix table color.
+ Change warning/tip/important tip color.
+ Change font to Titillium Web.
+ Other changes that's easier on eyes.