This is a workaround for a bug where signature verification would
overwrite the variable holding the signature.

This only happens on python2.

Signed-off-by: Damir Jelić <poljar@termina.org.uk>

OLMKit: Expose PK private key length

CMake support

OLMKit: Add objc wrappers for pk encryption/decryption

zero buffers in the JavaScript bindings

Poljar's improved python bindings

also reduce the amount of memory copying that we do

since they're not for the right repository any more

- build both Python2 and Python3 libs by default, and add separate rules
  building Python2 and Python.
- use the libraries as built by setuptools, rather than building again
  separately