Add better error messages in two cases

Using Python2
Terminal is too small for gui

pycgtool.py

@@ -3,9 +3,12 @@
 import argparse
 import sys
 
+try:
     from pycgtool.pycgtool import main, map_only
     from pycgtool.interface import Options
     from pycgtool.functionalforms import FunctionalForms
+except SyntaxError:
+    raise RuntimeError("PyCGTOOL requires Python 3.2 or greater")
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Perform coarse-grain mapping of atomistic trajectory")

pycgtool/interface.py

@@ -146,7 +146,10 @@ class Options:
 
         for i, (key, value) in enumerate(self):
             window_keys.addstr(i, 0, key)
+            try:
                 text_edit_wins.append(window_vals.derwin(1, 30, i, 0))
+            except curses.error as e:
+                raise RuntimeError("Your terminal is too small to fit the interface, please expand it") from e
             text_edit_wins[-1].addstr(0, 0, str(value))
             text_inputs.append(curses.textpad.Textbox(text_edit_wins[-1]))