Made a few changes to begin implementing easy mode

Mostly to begin making an easy mode but a few misc changes, including:
- When in easy mode, base healing has been bumped from 5 to 10.  Combos
still increase in increments of 5.
- In easy mode, melee enemies deal 5 damage instead of 10
- Option can be toggled by going to the options menu and hitting 'e'.
Overhaul of options menu coming soon.
- David's title in credits no longer has "Self Proclaimed"
- High Scores are tracked separately for easy/hard mode
Increased tile fall speed
Beginning of option menu overhaul

I am going to turn this into something that you can scroll up and down,
and will have a state machine similar to the pause menu so you can
change volume settings here as well.

Conflicts:
	Assets/Scripts/OptionsMenu.cs
More options menu stuff

Menu is turning into an array of MenuItem objects.  MenuItem is not
used, but has derived classes for different types of menu items (title,
toggleable option, selction).  Not fully implemented, previous
functionality is unchanged.
Scrolling options
Options now scroll.  Does not yet respond to touch.  Debug options on the options menu:
e: toggle easy mode (there is now a button that handles this)
o: scroll menu one direction
l: scroll menu the other direction
p: print out a value that i am still debugging

There is a large gap, this will eventually be used to allow for editing volume settings.

Conflicts:
	Assets/Scripts/OptionsMenu.cs
Options scroll (?)

I got some code from the unity api that I think will handle scrolling.
Untested on a touch device, doesn't work in editor.

Conflicts:
	Assets/Scripts/OptionsMenu.cs
Added in volume settings to options

Options how have a very simple state management so they can toggle
between options and volume adjustment.  Volume adjustment has also been
implemented.  Scrolling is still untested on a touch device.

Conflicts:
	Assets/Scripts/OptionsMenu.cs
Fixed a bug

You could tap over the flavor text of one option and change the one
above it... this has been fixed.  It was a leftover from when I was
using text on this screen instead of images.
Better scrolling

I realized changing a couple lines might make the scrolling more
natural.  Still haven't tested cause I can't deploy the apk anymore.