added project files

WORKPLAN.md

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+The idea is to be able to handle mergers and sinking galactic satellites by 
+having each subsystem centered on one (massless?) particle, and have the 
+expansion calculated separately in each center of mass system (only for 
+particles belonging to it). After the internal forces are calculated for each 
+subsystem, the mutual forces are calculated as well, and all the particles are 
+integrated in a global coordinate system.
+
+Technically, most of the SCF module has to become a class. Some of the arrays 
+like RadCoeff and AngCoeff (anything else?) should remain global and would be 
+initialized by some global initialization routine. Then each subsystem would be 
+a different instance of the SCF class, with its own list of coefficients and 
+particle cache. It seems that all subsystems can (should?) share the integrator 
+object. Maybe (probably?) the integrator should be agnostic to how particles are 
+divided into subsystems, and the call to CalculateGravity() would take care of 
+everything. In this case we are talking about a class for the current SCF 
+routines but also some wrapper that knows how to CalculateGravity() by calling 
+the appropriate methods for each subsystem's object, and also work out the 
+mutual gravity. Need a good name for this intermediate level between the 
+integrator and the SCF core.
+
+This intermediate level or even a different class would deal how to associate 
+particles to the different subsystems and how to figure out the initial 
+conditions. Also, the central particles might need some special treatment 
+(possibly the integrator considers them normal particles but this other level 
+knows not to use them for force calculation; I should think whether those should 
+be omitted from output, but it might be helpful to keep them).