First version for timer (RFC4028) timer support
First test
UAC and UAS rework
Partial tests
Merge branch 'refs/heads/master' into rfc4028_timer
Timer updates
Timers rework
Minor updates
Support for automatic BYE on timeout

Except for proxies
Add uac refresher option in subsequent refreshes
Minimal change
Add function 'store_value/3' to nksip_util
Clarify 'meta' usage in records
Created function 'update_min_se/2'
Minor refactor
Minor refactor
Move from lists:keystore/4 to nksip_lib:store_value/2
Added function 'require/2'
Updated nksip_parse:session_expires/1
Added option to use tokens in nksip_headers module