Agios 193

@danbev @cvasilak this PR is linked to:
https://github.com/aerogear/aerogear-ios-cookbook/pull/29

As dsicussed we have a list of TODO in https://github.com/aerogear/aerogear-ios-cookbook/pull/29 and tracked in JIRA tickets to improve it.

This is initial code for secure storage of tokens.