Sweeping for singularities and parameter continuation in PHCv2.4.87

For clarity, this directory was isolated from Continuation in v2.3.75.
The path trackers in this directory rely on natural parameter homotopies.

Run "gprbuild sweep.gpr" to make all test programs.
On windows, type "gprbuild sweep.gpr -Xos=windows"
at the PowerShell prompt.
The "gprclean sweep.gpr" removes all files created by gprbuild.

------------------------------------------------------------------------------
file name                        : short description
------------------------------------------------------------------------------
standard_parameter_solutions     : selecting and joining variables
dobldobl_parameter_solutions     : parameter solutions with double doubles
quaddobl_parameter_solutions     : parameter solutions with quad doubles
standard_parameter_systems       : definition of parameter homotopy + i/o
dobldobl_parameter_systems       : parameter homotopy with double doubles
tripdobl_parameter_systems       : parameter homotopy with triple doubles
quaddobl_parameter_systems       : parameter homotopy with quad doubles
pentdobl_parameter_systems       : parameter homotopy with penta doubles
octodobl_parameter_systems       : parameter homotopy with octo doubles
decadobl_parameter_systems       : parameter homotopy with deca doubles
hexadobl_parameter_systems       : parameter homotopy with hexa doubles
complex_convex_continuation      : interpolate start and target with complex
parameter_homotopy_continuation  : drivers to path tracking
ts_parcon                        : stand-alone calling program
------------------------------------------------------------------------------
standard_quad_parameters         : manages sweep numerical parameters
dobldobl_quad_parameters         : numerical parameters as double doubles
quaddobl_quad_parameters         : numerical parameters as quad doubles
standard_quad_turn_points        : location of quadratic turning points
dobldobl_quad_turn_points        : location in double double precision
quaddobl_quad_turn_points        : location in quad double precision
standard_quad_turn_points_io     : some input and output routines
dobldobl_quad_turn_points_io     : i/o for the double double version
quaddobl_quad_turn_points_io     : i/o for the quad double version
standard_quad_sweepers           : sweeper for singularities along a path
dobldobl_quad_sweepers           : double double sweeper for singularities
quaddobl_quad_sweepers           : quad double sweeper for singularities
ts_realcont                      : development of real path tracking
------------------------------------------------------------------------------
