siteSign accepts absolute paths as well as paths relative to working directory

- also store working_dir in config so it's possible to use from other
  actions as well

fixes #209

zeronet.py

@@ -123,6 +123,7 @@ def restart():
 
 
 def start():
+    config.working_dir = os.getcwd()
     app_dir = os.path.dirname(os.path.abspath(__file__))
     os.chdir(app_dir)  # Change working dir to zeronet.py dir
     sys.path.insert(0, os.path.join(app_dir, "src/lib"))  # External liblary directory