Make kamikaze timer loops use level.num_entities instead of MAX_GENTITIES

Optimization. Many other loops use level.num_entities, there was no
special reason that MAX_GENTITIES was used for these.
Update and rename README to README.md

adding analytics, I'm ready for DevHC to get upset.
Improve github interperation of README.md
Add header for standalone game licensing
Add project files converted to VS2005
Remove keys from shoot menu (in controls)
Change main menu
Make don't ask for cd-key
Change skirmish/server menu
Make you can select a weapon when choosing a team

You can do it from the UI or the console, for example:  team red rg for railgun. If you don't choose a weapon it selects a random weapon (RL or RG).

Also, RL and RG are registered when the game starts, instead of MG and gauntlet
Make don't toss items
Fix "LOW AMMO" warning when ammo = -1 (infinite)
Move the alternate weapon code to the end of ClientSpawn
Make bots work without items

Items are invisible and can't be grabbed.