Lock down truncate_html version to 0.5.x.
Lock down truncate_html version to 0.5.x.

Next version after 0.5.5 is 0.9 and it dropped Ruby 1.8.7 support but
we're still supporting it.

bryanmtl/g-refinerycms,aguzubiaga/refinerycms,KingLemuel/refinerycms,Retimont/refinerycms,hoopla-software/refinerycms,mkaplan9/refinerycms,mabras/refinerycms,bricesanchez/refinerycms,Retimont/refinerycms,kelkoo-services/refinerycms,simi/refinerycms,kappiah/refinerycms,johanb/refinerycms,mkaplan9/refinerycms,mobilityhouse/refinerycms,mlinfoot/refinerycms,refinery/refinerycms,KingLemuel/refinerycms,mabras/refinerycms,aguzubiaga/refinerycms,anitagraham/refinerycms,mabras/refinerycms,mkaplan9/refinerycms,gwagener/refinerycms,kelkoo-services/refinerycms,stefanspicer/refinerycms,mlinfoot/refinerycms,chrise86/refinerycms,stefanspicer/refinerycms,hoopla-software/refinerycms,KingLemuel/refinerycms,louim/refinerycms,LytayTOUCH/refinerycms,anitagraham/refinerycms,simi/refinerycms,trevornez/refinerycms,chrise86/refinerycms,louim/refinerycms,stefanspicer/refinerycms,johanb/refinerycms,refinery/refinerycms,bryanmtl/g-refinerycms,gwagener/refinerycms,trevornez/refinerycms,simi/refinerycms,Eric-Guo/refinerycms,kappiah/refinerycms,mobilityhouse/refinerycms,Eric-Guo/refinerycms,anitagraham/refinerycms,Retimont/refinerycms,aguzubiaga/refinerycms,bricesanchez/refinerycms,chrise86/refinerycms,hoopla-software/refinerycms,gwagener/refinerycms,johanb/refinerycms,simi/refinerycms,sideci-sample/sideci-sample-refinerycms,kappiah/refinerycms,Eric-Guo/refinerycms,LytayTOUCH/refinerycms,trevornez/refinerycms,refinery/refinerycms,sideci-sample/sideci-sample-refinerycms,LytayTOUCH/refinerycms,mlinfoot/refinerycms