Prepare for next development iteration

Change-Id: I67febfc4b3b29cd48538c79e4520cd3f25944919
dtlssrtpdec: Fix memory leak

Change-Id: Iaf2ba3832402bbe7580ef5af5aea1af617a29207
dtlssrtpenc: Fix memory leak

Change-Id: I8691a75b6e40f50045844ef8bdd98e5f55ba072e
dtlssrtpenc: Protect critical region just like in dtlssrtpdec

Change-Id: I3f78e7111e9be19da54ef63ab2070034cffe81cc
Prepare release 1.0.6

Change-Id: I33224bc2f2e881376b9e0f62bfa72106d8b5127f