Python Script Exec

.. runs in thread to avoid blocking GUI actions but GUI
   will still wait for script to complete. ESC is trapped,
   but mechanism to stop script not implemented yet.

src/Python/PythonEmbed.cpp

@@ -34,6 +34,7 @@
 
 // global instance of embedded python
 PythonEmbed *python;
+PyThreadState *mainThreadState;
 
 PythonEmbed::~PythonEmbed()
 {
@@ -81,11 +82,19 @@ PythonEmbed::PythonEmbed(const bool verbose, const bool interactive) : verbose(v
     PyErr_Print(); //make python print any errors
     PyErr_Clear(); //and clear them !
 
+    // prepare for threaded processing
+    PyEval_InitThreads();
+    mainThreadState = PyEval_SaveThread();
+
     loaded = true;
 }
 
+// run on called thread
 void PythonEmbed::runline(QString line)
 {
+    PyGILState_STATE gstate;
+    gstate = PyGILState_Ensure();
+
     // run and generate errors etc
     messages.clear();
     PyRun_SimpleString(line.toStdString().c_str());
@@ -107,7 +116,7 @@ void PythonEmbed::runline(QString line)
         // clear results
         PyObject_CallFunction(static_cast<PyObject*>(clear), NULL);
     }
-
+    PyGILState_Release(gstate);
 }
 
 void