Mejiro update

I wanted to add a simple search feature to Mejiro, and I ended up spending several evenings tweaking and improving the application. Here's a short changelog:

• Added a search feature that makes it possible to search by file names.
• Replaced Barlow typeface with Inter.
• Added the download.php script that handles and keeps track of downloads.
• Names of the downloaded files are stored in the downloads.txt file. If the file exists, the stats.php page now features the Downloads section that displays the total number of downloads, and number of downloads for each file.
• Downloads can now be protected with a password.
• GoatCounter integration has been removed.
• Various cosmetic tweaks and minor fixes.