Add Account management class
observing accessToken changes
Podspec addition for AGAccountManager
syntax error podspec
simplify account mgr interface
simplify account mgr interface
dependency clean up
fix saving issue
implement KVO on authz accessToken
Configurable persistent type
Observer refresh and expriration date
Remove unneeded clientId
fix typo
refactor to inject a store, name as the accountId and polishes
revert to accountId
Merge branch 'AGIOS.190.account'