BUG: Missing binary Examples folder

`RunExamples` has been moved from `ITKSoftwareGuide/SoftwareGuide/Examples`
to a CMake `ExternalProject_Add`. This means that the subfolder
`ITKSoftwareGuide/SoftwareGuide/Examples` is not created a configure time
anymore. When Examples are parsed to be converted to `tex` files, the parser
fails to write the generated `tex` file as the output folder does not
exist.

Author: Francois Budin

SoftwareGuide/Examples/ParseCxxExamples.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 import sys
 import os
+import errno
 import re
 import shlex
 import subprocess
@@ -156,6 +157,15 @@ def GetPreambleString(examplefilename):
 
     thisCodeBlocks = ParseOneFile(inputfilename)
 
+    try:
+        path = os.path.dirname(outputfilename)
+        os.makedirs(path)
+    except OSError as exc:  # Python >2.5
+        if exc.errno == errno.EEXIST and os.path.isdir(path):
+            pass
+        else:
+            raise
+
     outPtr = open(outputfilename, 'w')
     outPtr.write(GetPreambleString(inputfilename))
     for cb in thisCodeBlocks: