zulmargera87's MP5 - audiovisual update

An update of the original zulmargera87's MP5/M203. More detailed credits are included in the .rar file. Please don't flag - I made SURE every author is credited properly.

List of things I changed/added:

• added a full set of new sounds
• added a new muzzleflash by Strelok
• added a new grenade.mdl and shell.mdl model
• added new grenade explosion effects from DiamonD's Half-Life pack
• slightly changed the origins
• changed the hand textures to H4wk's

Didn't modify the actual MP5 model in any way.