Decouple fps tps

[Hambones82]

This pull request attempts to address #997. First, in framework.cpp, a new whileloop is added around currentstage.update() which runs on a ticks per second basis, rather than being in lockstep with stage.render(). The code also includes various changes related to ticks_per_second and related constants, throughout a number of files. The code also moves the ticks_per_second constants into framework.h, in order to allow the state update loop to run on a ticks_per_second basis. This assumes a 1:1 correspondence between in-game seconds at the slowest speed and real-time seconds. Later, we might consider moving the time constants back into gametime.h and having a single number that is ticks per real second (or something), as well as ticks_per_sim_second, with a relation between the two.

Re the change to doodad, it now has a magic number which is bad. I'm not sure what it should be, though... It was originally ticks_multiplier, which I thought I knew what it meant but now I'm not so sure.

[FilmBoy84]

Regarding Doodad.cpp do we want to hardcode this value of four if we move to a variable simulation rate?

[Hambones82]

You are right. I think it will make sense to create a new constant for doodads in doodad.h. I'll update it.