Allow for a negative value ('no') to be sent in the POST array to un-tick a checkbox.
Allow for a negative value ('no') to be sent in the POST array to un-tick a checkbox.

Signed-off-by: Alistair Kearney <e9adbcf81c8a36ccc628e09bc92d0e25e1c8e501@21degrees.com.au>
henrysingleton/litmusk,ayellowraven/projectplaten,NikoMostWanted/symphony-2,bauhouse/Bugaroo,eliksir/norske-webapps,michael-e/symphony-2,pixelninja/imagick_effects,psychoticmeow/symphony-2,bauhouse/sym-barebones,scottkf/nicholscommunications,embarknow/journey-cms,eliksir/norske-webapps,builders/collective,psychoticmeow/journey-cms,bauhouse/sym-pears,bauhouse/sym-pagoda,mazedigital/jcilearn,psychoticmeow/symphony-2,Titch/Symph-test,DeuxHuitHuit/symphony-2,nils-werner/Bugaroo,symphonycms/symphony-3,tachyondecay/symphony-2,psychoticmeow/journey-cms,builders/collective,BloodBrother/symphony-2,Titch/Symph-test,DeuxHuitHuit/symphony-2,roshinebagha/Symphony-Test,blaXXabla/projet_test_symphony,BloodBrother/symphony-2,bauhouse/sym-pears,alexnantel88/symphony-2,embarknow/journey-cms,yojeek/sym-community,astudio/remixhair,benesch/hilton-unar,wastemobile/Symphony2.3.6,brendo/symphony-2,embarknow/journey-cms,bauhouse/Piano-Sonata,bauhouse/sym-intranet,jdsimcoe/symphony-boilerplate,ahwayakchih/symphony-2,symphonycms/symphony-2,jdsimcoe/symphony-boilerplate,jonmifsud/symphony-2,roshinebagha/Symphony-Test,bauhouse/members-forms-ensemble,avanteweb/symphony-2,jonmifsud/symphony-2,benesch/hilton-unar,bauhouse/members-forms-ensemble,scottkf/keepflippin--on-symphony,symphonycms/sym-getsymphony,thebestsophist/personal-health-diary,bauhouse/sym-site,bauhouse/sym-intranet,nils-werner/Bugaroo,bauhouse/designadmin,builders/sym-bauhouse-ensemble,bauhouse/sym-extensions,scottkf/premier-medical-care.com,bauhouse/Bugaroo,scottkf/premier-medical-care.com,mazedigital/jcilearn,twiro/symphony-2,tachyondecay/symphony-2,rzantolas/Symphony-Test,psychoticmeow/journey-cms,builders/sym-bootstrap,symphonycms/sym-getsymphony,embarknow/journey-cms,avanteweb/symphony-2,eliksir/norske-webapps,DavidForster/symphony-2,builders/designadmin,psychoticmeow/journey-cms,wastemobile/Symphony2.3.6,chay83/Symphony-Shopping-Cart-Ensemble,bauhouse/sym-forum,jensscherbl/symphony,brendo/symphony-2,jensscherbl/symphony,bauhouse/sym-pagoda,builders/sym-bootstrap,bauhouse/sym-calendar,ljonka/symphony-2,ayellowraven/projectplaten,bauhouse/sym-form-builder,bauhouse/sym-spectrum-members,symphonycms/symphony-2,allen/auth.getsymphony.com,DavidForster/symphony-2,davjand/Checkout-Ensemble,bauhouse/sym-fluidgrids,psychoticmeow/journey-cms,rzantolas/Symphony-Test,mazedigital/jcilearn,astudio/remixhair,jdsimcoe/symphony-boilerplate,TheJester12/issueprompt,jurajkapsz/symphony-2,NikoMostWanted/symphony-2,scottkf/nicholscommunications,twiro/symphony-2,johnpuddephatt/symphony-2,domain7/sym-cumulus,jdsimcoe/symphony-boilerplate,michael-e/symphony-2,symphonycms/symphony-3,davjand/Checkout-Ensemble,jurajkapsz/symphony-2,ahwayakchih/symphony-2,ljonka/symphony-2,scottkf/premier-medical-care.com,embarknow/journey-cms,TheJester12/issueprompt,bauhouse/Piano-Sonata,bauhouse/sym-connector,bauhouse/sym-todo-list,bauhouse/sym-spectrum,chay83/Symphony-Shopping-Cart-Ensemble,TheJester12/issueprompt,alexnantel88/symphony-2,bauhouse/sym-todo-list,allen/auth.getsymphony.com,thebestsophist/personal-health-diary,yojeek/sym-community,johnpuddephatt/symphony-2,henrysingleton/litmusk,blaXXabla/projet_test_symphony