PythonEditor: Add a run configuration

Allows selection of the interpreter and commandline parameters.

Also add support for ".pyqtc" as a project file, containing
a flat list of .py files, similar to the Generic Project.

Change-Id: If75a0affd735223a658ce7fce0d010ebf49695f2
Reviewed-by: hjk <hjk@theqtcompany.com>
Reviewed-by: Nikita Baryshnikov <nib952051@gmail.com>
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/pythoneditor/PythonEditor.mimetypes.xml

@@ -5,4 +5,9 @@
         <comment>Python source file without console</comment>
         <glob pattern="*.pyw"/>
     </mime-type>
+    <mime-type type="text/x-python-project">
+        <sub-class-of type="text/x-python"/>
+        <comment>Qt Creator Python project file</comment>
+        <glob pattern="*.pyqtc"/>
+    </mime-type>
 </mime-info>