new ui and argument handling

caverna is planned to have various player attributes such as: hp, mana, and hunger. because of this, the old ui didn't make much since, and it was copied from the rltk rogue like tutorial. this new ui allows for more information to be displayed at a time. unfortunately this new ui doesn't display the event log like in the old ui. the plan is to change the window scale and size to allow for the world size to not be affected, because currently the ui cuts space from the world's dimensions. the event log will come in a similar form to the old ui.  

i want to add some form of developer commands into the game. of course, in the final release these commands will still be available to everyone. currently commands are read from arguments passed through by cargo. below is an example of what this looks like:

cargo run -- debug seed 39 noclip player_view_range 4

this change brought the following commands/arguments: debug, unscaled, fullbright, starting_item, seed, noclip, nogui, blank_world, player_view_range.

• debug: shows the debug ui (screenshot below).
• unscaled: removes the scale factor from the window, this causes everything to become super small. 
• fullbright: makes every block visible. 
• starting_item #: requires a block id directly after, if the block id isn't valid or isn't filled the game will panic. 
• seed #: requires a custom seed after, if this field is left empty the game will panic. 
• noclip: turns off block collisions with the player. 
• nogui: turns off the gui. 
• blank_world: fills the world with empty blocks.
• player_view_range #: this changes how far the player can see without fullbright. anything higher than 16 will cause performance issues, and if the # field is left empty, the game will crash.