Added a Species Registry to load microbe species from XML,
and modified microbe spawning code to use the species data. Some new ai microbe
species have joined the party, and modders can easily make more just by modifying
two files (scripts/microbe_stage/setup.lua for spawning parameters, and
assets/definitions/microbes.xml for the species). OrganelleFactory was also
refactored to make it easier to create new organelles -- one need not edit
OrganelleFactory.makeOrganelle anymore. Fixes #184
Merge pull request #185 from Revolutionary-Games/184-xml-microbes

184 xml microbes
Added a Species Registry to load microbe species from XML, and modified microbe spawning code to use the species data. Some new ai microbe species have joined the party, and modders can easily make more just by modifying two files (scripts/microbe_stage/setup.lua for spawning parameters, and assets/definitions/microbes.xml for the species). OrganelleFactory was also refactored to make it easier to create new organelles -- one need not edit OrganelleFactory.makeOrganelle anymore. Fixes #184