Resource stores needn't know what they store
Added convenience property to resource stores
Removed energy storage allele

Warning: everything is broken!
Fixed DigestionAllele

At least in terms of how it interacts with stored resources.  It still
fetches the alleles wrong (with the Gene enum).  Also, energy is a
floating point value now.
Removed nutrient storage allele

As it's been subsumed by the generic storage allele.  Note that, again,
everything is broken.
All the way removed nutrient storage allele

Pesky Unity/VS don't save their state to disk very quickly sometimes...
Fixed alleles broken by nutrient storage removal

HOWEVER they are not completely fixed, as they currently don't specify
which nutrient storage they want when they fetch a nutrient store
allele.  I'm waiting for the Gene enum refactor first.