yquake2 7.40 version.

Little more fixes in soft render. Quake II 7.30 to 7.40:

• Add support for HTTP downloads. Both the r1q2 and q2pro URL schemes are supported, if a file is unavailable over HTTP the download code falls back to UDP.
• Savegames can be removed through the menu by pressing 'del' on the selected savegame. (by Jonathan Bergeron)
• Support external entity files. This was submitted by @NeonKnightOA.
• Some fixes to OGG/Vorbis music playback. The music keeps playing after s_restart and ogg_shuffle is handled correctly by the menu.
• Another round of timing fixes. Average frame times are now taken into account when taking an educated guess on the next frames render time. And the display refresh rate detection no longer cripple working GPU drivers in an effort to work around bugs in older version of AMDs.
• A lot of fixes to the internal memory management. The game is now much more memory efficient, this allows playing of extremely big maps without crashes. This is largely based upon work done by Denis Pauk.
• New and much more detailed documentation.
• Enhancements to the software renderer. Retexturing packs are now supported, general cleanup and bugfixes. (by Denis Pauk)