* agent: retry loop that resumes subscriptions as soon as agent is moved to foreground, suspend retry loops while agent is suspended
* reset retry enterval when moving to foreground
* account for network state too
* simplify
* typo
* simplify
* send "quota exceeded" message from SMP server when sender gets ERR QUOTA (ignored in the agent for now)
* send msg quota to the recipient to indicate that sender got ERR QUOTA, test
* switch between slow/fast retry intervals (tests do not pass yet)
* send QCONT message, refactor RetryInterval, test
* refactor
* remove comment
* remove space
* unit test for withRetryLock2
* refactor