Fixed segfaults in poly __new__ and pgPolygon_FromObject

[itzpr3d4t0r]

This pull request resolves issue #171, and is a direct continuation of #157. The changes made include:

• The Polygon.__new__ function now always allocates memory for three vertices, meaning it creates a triangle. It's important to note that all vertices will have uninitialized data. It's a waste of performance to set all vertices to 0.
• The init function now resizes the memory that __new__ allocated if more than three vertices need to be allocated.
• Slight simplifications in pgPolygon_FromObject, moved around some *was_sequence = 1s.
• Fixed another issue that caused pgPolygon_FromObject to segfault when lists or tuples were passed as polygons

And The following program no longer segfaults:

from geometry import Polygon

poly = Polygon.__new__(Polygon)

poly[0] = (1, 2)