Gh2 mnemonics and pulse alignment

Update the GH2 mnemonics and add a function to extract the exposed frames.

src/toolbox_scs/detectors/__init__.py

@@ -5,6 +5,7 @@ from .dssc import *
 from .dssc_data import *
 from .dssc_misc import *
 from .dssc_processing import *
+from .gotthard2 import *
 from .hrixs import *
 from .pes import *
 from .viking import *
@@ -18,6 +19,7 @@ __all__ = (
     + dssc_data.__all__
     + dssc_misc.__all__
     + dssc_processing.__all__
+    + gotthard2.__all__
     + hrixs.__all__
     + pes.__all__
     + viking.__all__