Recent versions of Graphviz no longer set the PATH variable on Windows.
Hence Scyther can fail to find dot.exe even though Graphviz was appropriately
installed.
This patch is a hack to try and locate dot.exe in the more common locations.
We currently have a hardcoded search through:
C:\Program Files\Graphviz*
C:\Program Files (x86)\Graphviz*
This is clearly fragile. Obviously, nobody should be solving Graphviz' problem
in such an ugly way. Change drives or languages and it stops working.
Until Graphviz provides at least an alternative environment variable (GVPATH?)
this hack will help the bulk of our users to get things up and running smoothly.
Before, we were using both __file__ as well as sys.argv[0] to determine the base directory
for Scyther, and we were not taking symlinks into account.
By using the inspect module, we can consistently pick the current frame and derive
the file from that, then use realpath to strip symlinks.
Current wxPython packages only work in 32-bit mode. If we detect that there is
an error message complaining about the architecture, we restart scyther-gui.py using
python in 32-bit mode.
If wxPython is not present, there would be a command-line message only.
Some users may not notice that. We now fall back to Tkinter to report
such messages.
