updated changelog for v0.8.2
updated changelog for v0.8.2

Eric-Guo/savon,enahum/savon,rtrepo/savon,savonrb/savon,payfriendz/savon,latortuga/savon,mpangrazzi/savon,viniciusnz/savon,advishnuprasad/savon,oafridi/savon,billr578/savon,travis-repos/savon,BlaneCordes/savon_vertex,zerobatu/savon,kimptoc/Savon-with-username-token-digest,SICSoftwareGmbH/savon