gendisk (and gendisk2d)

[The9Cat]

1. I changed the gendisk (initial.cc) parameters to be consistent with our new parameter choices.
2. I added a gendisk2d (initial2.cc) which is a port of initial.cc of DiskHalo.cc to use the flat disk eof evaluator (BiorthCyl.cc) rather than the 3d eof (EmpCylSL.cc).

This is an interim solution. A better strategy would be an overall of the entire gendisk system to include:

1. An arbitrary number of components
2. A class hierarchy that fits all cylindrical and spherical components into a single framework to eliminate the duplication between the 2d and 3d disks.