Update `Symphony.Message.post()` and `Symphony.Message.clear()` to work with new backend markup
Update `Symphony.Message.post()` and `Symphony.Message.clear()` to work with new backend markup

Related to #840

johnpuddephatt/symphony-2,NikoMostWanted/symphony-2,alexnantel88/symphony-2,jurajkapsz/symphony-2,ayellowraven/projectplaten,symphonycms/sym-getsymphony,symphonycms/symphony-2,mazedigital/jcilearn,brendo/symphony-2,bauhouse/sym-todo-list,mazedigital/jcilearn,jonmifsud/symphony-2,bauhouse/sym-todo-list,symphonycms/sym-getsymphony,DavidForster/symphony-2,thebestsophist/personal-health-diary,wastemobile/Symphony2.3.6,bauhouse/Piano-Sonata,jurajkapsz/symphony-2,blaXXabla/projet_test_symphony,rzantolas/Symphony-Test,ljonka/symphony-2,wastemobile/Symphony2.3.6,thebestsophist/personal-health-diary,mazedigital/jcilearn,brendo/symphony-2,ayellowraven/projectplaten,bauhouse/sym-pears,allen/auth.getsymphony.com,BloodBrother/symphony-2,roshinebagha/Symphony-Test,twiro/symphony-2,johnpuddephatt/symphony-2,astudio/remixhair,bauhouse/Piano-Sonata,alexnantel88/symphony-2,bauhouse/sym-pears,twiro/symphony-2,jonmifsud/symphony-2,BloodBrother/symphony-2,jdsimcoe/symphony-boilerplate,jdsimcoe/symphony-boilerplate,DeuxHuitHuit/symphony-2,roshinebagha/Symphony-Test,avanteweb/symphony-2,michael-e/symphony-2,astudio/remixhair,blaXXabla/projet_test_symphony,NikoMostWanted/symphony-2,DeuxHuitHuit/symphony-2,ljonka/symphony-2,michael-e/symphony-2,jensscherbl/symphony,allen/auth.getsymphony.com,jensscherbl/symphony,jdsimcoe/symphony-boilerplate,rzantolas/Symphony-Test,avanteweb/symphony-2,jdsimcoe/symphony-boilerplate,symphonycms/symphony-2,DavidForster/symphony-2