Split iodine as a git submodule

this MR removes iodine from the andiodine tree and re-adds it as a git submodule. the advantage is that now both repos can evolve more or less independently.

the changes to iodine necessary for andiodine are applied over yarrick's repo in a small set of commits you'll find in my iodine repo here (fork of his). these changes were streamlined or re-authored a bit, with the aim of being easy to apply over other versions or forks of iodine that one might want to use with andiodine (which is the reason i did all this in the first place).

besides merging this MR, you probably want to fork my iodine repo and then change the submodule definition in this repo to point to your fork of iodine to fully retain control of official andiodine.

NOTE: i have no idea how submodules affect travis or whatever technology F-Droid uses for build automation. additional tweaks might be required to make fdroid's build bot happy.