MNT: Add gitpython and twine to "dev" extra

Author: effigies

setup.cfg

@@ -43,6 +43,9 @@ include_package_data = True
 [options.extras_require]
 dicom =
     pydicom >=0.9.9
+dev =
+    gitpython
+    twine
 doc =
     matplotlib >= 1.3.1
     mock
@@ -58,7 +61,9 @@ test =
     pytest
 all =
     %(dicom)s
+    %(dev)s
     %(doc)s
+    %(style)s
     %(test)s
 
 [options.entry_points]