Update README.md 

ported to 4.15 

fixed autodetection for PyFbxFactory 20tab#488

Merge pull request 20tab#504 from heylenz/master pyactor add function "set_actor_hidden_in_game"

added set_brutal_finalize() 

fixed 4.18 

Update MemoryManagement.md 

include 4.20 in automatic builds 

python2.7/python3.5 fixes 

prepare automated builds for python 3.7