avoid python warning

..\pythonscript\installer\extractVersion.py:7: SyntaxWarning: invalid escape sequence '\P'

Author: chcg

installer/extractVersion.py

@@ -4,7 +4,7 @@
 import sys, os
 import re
 
-pathToVersionFile = os.path.join(os.path.abspath(os.path.dirname(sys.argv[0])), '..\PythonScript\src\PythonScriptVersion.h')
+pathToVersionFile = os.path.join(os.path.abspath(os.path.dirname(sys.argv[0])), '..\\PythonScript\\src\\PythonScriptVersion.h')
 
 versionHeader = open(pathToVersionFile, 'r')
 versionRegex = re.compile(r'PYSCR_VERSION_STRING\s+"([0-9.]+)"')