v2.5.0

• Add external-link icon. Programming language icons now white instead of light blue because some of them are associated with certain brand guidelines.
• Experiment with new favicons.
• Hide scrollbar in sidebar when not needed.
• Remove XKCD browser from Projects and add Kotlin to Narradir.
• Use span to get rid of weird highlighted white space at end of h4 that seemed to be caused by font-size property in CSS (observable at the end of titles of carousel for Text-Popover).
• Bump version of Native Carousel, fixing wrongly-centered < and > in Firefox and Safari.
• Remove clickability of conway/rules.jpg.
• More refactoring with Jekyll.
• Miscellaneous text changes and re-organisations, including programming icon categories.