Bump to 3.7.0a4

Include/patchlevel.h

@@ -20,10 +20,10 @@
 #define PY_MINOR_VERSION        7
 #define PY_MICRO_VERSION        0
 #define PY_RELEASE_LEVEL        PY_RELEASE_LEVEL_ALPHA
-#define PY_RELEASE_SERIAL       3
+#define PY_RELEASE_SERIAL       4
 
 /* Version as a string */
-#define PY_VERSION              "3.7.0a3+"
+#define PY_VERSION              "3.7.0a4"
 /*--end constants--*/
 
 /* Version as a single 4-byte hex number, e.g. 0x010502B2 == 1.5.2b2.

README.rst

-This is Python version 3.7.0 alpha 3+
-=====================================
+This is Python version 3.7.0 alpha 4
+====================================
 
 .. image:: https://travis-ci.org/python/cpython.svg?branch=master
    :alt: CPython build status on Travis CI