use get_access_token in signed_session, to ensure the Authorization t… …oken in the session is not expired (microsoft#602)

Merge pull request microsoft#536 from microsoft/eric/fixGetTeamsConne… …ctorClient Teams connector client creation cleanup

Merge pull request microsoft#370 from microsoft/axsuarez/fix-appinsig… …hts-setup Adding processor as exported package

Initial template for echo bot (microsoft#351) 

Add missing flask package (microsoft#300) (microsoft#301) 

Merge pull request microsoft#245 from microsoft/daveta-core101 Corebot 101 initial checkin

Merge pull request microsoft#96 from Microsoft/4.0.0.a6 4.0.0.a6

Merge pull request microsoft#92 from Microsoft/v-stgum/TurnContext rename BotContext to TurnContext