[RELEASE] Released version 1.3.15.2

[RELEASE] Released version 1.3.15.2

Released version 1.3.15.2 with the following main changes :
    - [BUILD] make install should depend on haproxy not "all"
    - [BUG] event pollers must not wait if a task exists in the run queue
    - [BUG] queue management: wake oldest request in queues
    - [BUG] log: reported queue position was offed-by-one
    - [BUG] fix the dequeuing logic to ensure that all requests get served
    - [DOC] documentation for the "retries" parameter was missing.