Difficulty update

First time using the actual merge request feature, I might have done something incorrectly.

Just a quick update to difficulties that I've decided should be there regardless of what form the start zone rescaling takes.  The loss of stats on higher difficulties is very arbitrary and removing it helps simplify the ruleset which is good for balancing and player understanding.  Instakill immunity protects against a number of things that force turn skips, and absolutely nobody finds dying to Stone Touch fun or interesting.  Its just random and stupid.

Forced start zones allowing rares is almost certainly going to be a problem no matter how well scaling is addressed.

Newshop

Adds a lite/digger shop to Derth and the Iron Council.
Also added in the missing alchemist reference in the derth.tmx. No idea why it wasn't there.
Could use a new shop banner.

Shiftingparticles

Checked every instance of addParticles and addEffect to identify particle emitters that should use the new flag, and added it.

- Removed the instakill and rank changes for higher difficulties to normalize the ruleset

Targeting hooks

Makes extending the targeting system a lot easier:

- Moves all the different targeting types into Target.types_def
- Adds a Target:realDisplay hook.
- Target tables can now take a filter(x, y) function.
- Lifts a lot of the display code into functions which the targeting table can override.

Shifting particles

Particle systems can now react to actor movements

Merge branch 'master' into shifting_particles

Conflicts:
	game/engines/default/engine/Actor.lua
	game/engines/default/engine/Entity.lua
	game/modules/tome/class/Actor.lua

Sustain slots

Lets you easily define mutually incompatible sustains, like Chants.

For each chant, just add the line:
sustain_slots = 'celestial_chant'

Talents using this system will show what they'll deactivate in the tooltip.

I ran through and switched a lot of talents over to using this system.

example: sustain_slots = 'celestial_chant'
Changed most sustains to use the system.
Talent tooltips will show if they will deactivate anything.

Gem restructure

Restructures how gems work.

Moved most of the gem color information for various talents into a table.
Now more amenable to adding new gem colors.
Tirakai's Maul can have gem interactions defined easier.
Goedalath Rock now gives golems shadowflame damage.
Shadowflame damage type now has a text color.
Gems show their 'latent damage type' on tooltips.

Debug entity upvalue

Fix temporal bolt error.

Debug entity upvalue

So it turns out arrows have lurking upvalues...

I rewrote table.check so it gives more information and can be passed a do_recurse function. (So I could actually find the upvalues).
I gave talents and talent-types a __CLASSNAME field so they're not treated as tables to be copied. (And so aren't checked for upvalues).
A projectile's "def" table now has an _allow_upvalue flag, to account for the "block" upvalue that's already accounted for in the code.

Simple bugfixes

If you're pinned, a swap with a friendly still takes energy.

Was going to outright disable it, but doctornull talked me out of it?

Debug entity upvalue

Moves the upvalue checker into Entity:init, so that entities created by talents and such get run through it as well.