Method for solving a PnP problem.

Values of this enumeration:

• SOLVEPNP_ITERATIVE
• SOLVEPNP_EPNP
• SOLVEPNP_P3P
• SOLVEPNP_DLS
• SOLVEPNP_UPNP
• SOLVEPNP_AP3P
• SOLVEPNP_IPPE
• SOLVEPNP_IPPE_SQUARE