First patch for the ludum

Hey there, here some notes about some tweak and things that we forgot

Graph:

• Change building filters into point filters so they look less blury 
• Resize the size of the package to deliver
• Added a solid ground
• Replaced the tutorial panel
• Remplaced some fonts in the button UI
• Added Credits in game (we forgot the first time)
• Changed some layer so some things or more visible

Balance:

• Now the player with the package is a little bit slower
• Timer of a game set to 180sec instead of 120sec