fix librocket install instructions in readme
factored pause menu code out into module
add main menu
Merge pull request #94 from wheybags/mainMenu

Main Menu
switch to default-on collision
fix deleting levels which were null
enable clipping between the player and npcs
Merge pull request #97 from wheybags/npc-collision

enable clipping between the player and npcs
minor fix to librocket install instructions
adds custom keybindings
Merge pull request #98 from Exairnous/keybindings

adds custom keybindings
play music
Merge pull request #99 from wheybags/music

play music
slight change to how static libs are handled on windows
allow level generation for level 2 dungeons