Samurai and Zombie Asset sets!

Here's a whole new asset set while we are working on custom mesh importation! What's included?

New assets:

• 56 Zombies.
• 245 Props and building (including snow variants).
• 7 Samurai themed characters each 3 different colours.

Fixes:

• Hovering over a prop in the menu now displays the name.
• Input text validator stops incorrect map name format.
• Some other small optimizations and tweaks.