Merge pull request #19 from rayburgemeestre/network_multiplayer

Implement additional UDP connection on same port between client <> server
Fixed an include
Renamed connect to select server in client settings menu
The start button can now be used to select items in menus
Start button now quits in stead of unpauses when quit is selected
Renamed multiplayer to play local and online to play online in main menu
Fixed laser beam offset
Bomb sprite no longer cut off on the bottom
Fixed explosion offset for mines
changed bomb sprite, added magenta hightlight for menu
Switched default keymapping for player 1 and 2
Altered sprites for titlescreen
Merge pull request #36 from jeroen-groeneweg/network_multiplayer

Merged sprites and stuff from Jeroen
Title screen now has the Tweak Battle style
Menu bar colors changed to tweak battle style
Fixed props bitmap
If you pause the game in arcade mode time should not have further elapsed