Rationale:
pya.CplxTrans.angle is computed by doing atan2(m_sin, m_cos), but the algorithm used both in C and python for sin, cos and atan2 are not as precise as IEEE's float.
In python, for example, this happens:
``` python
>>> from math import pi, cos, sin, atan2
>>> atan2(sin(45*pi/180), cos(45*pi/180)) * 180 / pi == 45
False
>>> atan2(sin(45*pi/180), cos(45*pi/180)) * 180 / pi, 45
(44.99999999999999, 45)
```
The issue was caused by an internal error in the edge processor.
Effectively the weak attractor scheme was causing this problem.
As the weak attractors are making things worse rather than
better I dropped them.
In theory, the weak attractors render an edge undisturbed by
neighboring intersection points, but in cases or parallel edges
this lead to problems: omitting cut points violates the output
edge configuration warranties the the polygon stitcher fails.
In addition, to maintain the solution for bug #74, the cut point
capture condition was relaxed, so that edge crossing the exact
corner of the snapping rectangle of a point are not considered
captured.
This commit also contains some important fixes:
* Option -wd wasn't working
* Relative layout file paths in session files are resolved as relative
to the session file. On writing, absolute paths are used, so this
change only affects session files build intentionally.
Plus:
* Program version is available in unit tests too
* Fixed a typo in the RBA::Expression documentation
The fix consisted of introducing "factory" type virtual
methods which ensure that a reference is held to the
returned object. This is important for implementing
factory methods in Python. Without this, the object
get destroyed before we have a chance to increment the
reference count.
This commit adds "permissive" mode to OASIS writer to allow
odd-width paths (which are rounded).
This commit contains in addition:
* The check for odd-width paths is done post-scaling, so
reducing the DBU is a workaround
* Unit tests for the RBA binding of SaveLayoutOptions
* Documentation updates on some SaveLayoutOptions attributes
* Using Ruby predicate notation for cif_blank_separator?
(note question mark) for consistency. The old notation is
still there but deprecated
* --permissive option on buddies command lines where applicable