Add test to make sure supported table entries are added to git

Catches the vase where support for a table is added, but the .py
file is not added to git (like happened for feat and fvar tables).

Lib/fontTools/ttLib/tables/__init__.py

@@ -2,6 +2,8 @@
 def _moduleFinderHint():
 	"""Dummy function to let modulefinder know what tables may be
 	dynamically imported. Generated by MetaTools/buildTableList.py.
+
+		>>> _moduleFinderHint()
 	"""
 	from . import B_A_S_E_
 	from . import C_B_D_T_
@@ -58,3 +60,7 @@ def _moduleFinderHint():
 	from . import _s_b_i_x
 	from . import _v_h_e_a
 	from . import _v_m_t_x
+
+if __name__ == "__main__":
+	import doctest, sys
+	sys.exit(doctest.testmod().failed)