big rework to comply to current spec

- adapt to release(v2018-11-07)
- remove duplicate errors.py
- adapt tests

Change-Id: I383bb571f9808c72b37c12fbe55042011c4c0084
Reviewed-on: https://forge.frm2.tum.de/review/19397
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop/gui/params/__init__.py

@@ -134,7 +134,7 @@ class GenericCmdWidget(ParameterWidget):
         loadUi(self, 'cmdbuttons.ui')
 
         self.cmdLineEdit.setText('')
-        self.cmdLineEdit.setEnabled(self.datatype.argtypes is not None)
+        self.cmdLineEdit.setEnabled(self.datatype.argtype is not None)
         self.cmdLineEdit.returnPressed.connect(
             self.on_cmdPushButton_clicked)
 
@@ -164,7 +164,6 @@ def ParameterView(module,
                   parent=None):
     # depending on datatype returns an initialized widget fit for display and
     # interaction
-
     if datatype is not None:
         if datatype.IS_COMMAND:
             return GenericCmdWidget(