For development statically link dcc-rs

This links the python bindings statically to libdeltachat.a if the
DCC_RS_DEV environment variable is set to the project's root.  This is
a little simpler then requiring the manual CFLAGS and LD_LIBRARY_PATH
tweaking.

It also adds a script to easily invoke the integration tests locally
without forgetting steps.

.gitignore

@@ -11,3 +11,9 @@ include
 .dc-history.txt
 *.db
 *.db-blobs
+
+python/.eggs
+python/.tox
+*.egg-info
+__pycache__
+python/src/deltachat/capi*.so