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.
* import python, try to adapt for rust
* add missing wrapper functions
* - try to write up how to build python bindings
- strike some unused functions from deltachat.h
* adjustments to make tox work
* try to run circle-ci with python build
* don't do docs
* running cargo test as well
* don't run cargo test anymore, that's done in other ci jobs
* also build docs
* don't run doxygen anymore
* subst C with Rust
* a try to get better wheels
Closes#41
