[FIX] Axolotl 0.2.0 support

[Secret-Messenger-App]

BUG:

tgalal/python-axolotl@ef4a3d2

getRandomSequence MUST take an arg now:

05/10/2019 21:47:42: stderr: ERR: preKeys = KeyHelper.generatePreKeys(KeyHelper.getRandomSequence(),
05/10/2019 21:47:42: stderr: ERR: TypeError: getRandomSequence() takes exactly 1 argument (0 given)

FIX:

https://github.com/ReneVolution/profanity-omemo-plugin/blob/master/src/profanity_omemo_plugin/omemo/liteaxolotlstore.py

-- preKeys = KeyHelper.generatePreKeys(KeyHelper.getRandomSequence(),
++ preKeys = KeyHelper.generatePreKeys(KeyHelper.getRandomSequence(2**32 // 2),

[Secret-Messenger-App]

This also fixes:

#25
#31