Merge branch 'master' into poljar

.circleci/config.yml

CHANGELOG.rst

Makefile

README.rst

.../src/main/java/org/matrix/olm/OlmInboundGroupSession.java

...src/main/java/org/matrix/olm/OlmOutboundGroupSession.java

...olm-sdk/src/main/java/org/matrix/olm/OlmPkDecryption.java

...olm-sdk/src/main/java/org/matrix/olm/OlmPkEncryption.java

android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java

android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp

android/olm-sdk/src/main/jni/olm_pk.cpp

android/olm-sdk/src/main/jni/olm_session.cpp

docs/olm.rst

docs/signing.rst

exports.py

include/olm/error.h

include/olm/pk.h

javascript/.gitignore

javascript/externs.js

javascript/olm_inbound_group_session.js