Add Liquid regex replace filters
Add Liquid regex replace filters

Copied and tweaked the general idea from [here](https://github.com/Shopify/liquid/issues/202#issuecomment-19112872). Essentially using the same code that [Liquid uses](https://github.com/Shopify/liquid/blob/master/lib/liquid/standardfilters.rb#L185) for their `replace` filter.
ianblenke/huginn,shirshendu/huginn,Aluxian/huginn,cantino/huginn,dnjo/huginn-spotify-linker,ianblenke/huginn,johnleeming/huginn,TildeWill/huginn,niravaga/huginn,AdrianoCahete/huginn,eugenesvk/huginn,den53/huginn,ashmckenzie/huginn,dnjo/huginn-spotify-linker,Ishfal/huginn,VelocityGrowth/huginn,cantino/huginn,younata/huginn,satishgoda/huginn,andywenk/huginn,mikalauskas/huginn,mikalauskas/huginn,wxdublin/huginn,eugenesvk/huginn,marcusgadbem/huginn,chrisgogreen/huginn,den53/huginn,andywenk/huginn,pssaravanan/huginn,naiyt/huginn,toruta39/huginn,stephenanthony/huginn,nuentes/huginn,creativepsyco/huginn,mirko314/huginn,materliu/huginn,shaunaa126/huginn,duke-libraries/huginn,kyroskoh/huginn,rasata/huginn,ahmadassaf/IFTTT-Plus,ashmckenzie/huginn,run-project/huginn,flagsoft/huginn,mathias/huginn,armuk/huginn,naiyt/huginn,valeriosouza/huginn,MadBomber/huginn,bartoszkopinski/huginn,badrul/huginn,nuentes/huginn,kyroskoh/huginn,darrencauthon/huginn,djolivier/huginn,omniscopeio/huginn,andywenk/huginn,dobtco/huginn,dsander/huginn,whicheverpeady/huginn,johnleeming/huginn,MOZGIII/huginn,eugenesvk/huginn,cantonic/huginn,toruta39/huginn,badrul/huginn,bencornelis/huginn,stephenanthony/huginn,mindvalley/huginn,jezcope/huginn,ashmckenzie/huginn,albertsun/huginn,armuk/huginn,breandan/huginn,toruta39/huginn,omniscopeio/huginn,deanishe/huginn,chrisgogreen/huginn,shaunaa126/huginn,AdrianoCahete/huginn,azati/huginn,azati/huginn,rasata/huginn,flagsoft/huginn,nuentes/huginn,virtadpt/huginn,TildeWill/huginn,chrisgogreen/huginn,VelocityGrowth/huginn,shaunaa126/huginn,creativepsyco/huginn,ahmadassaf/IFTTT-Plus,CodeHunter2006/huginn,den53/huginn,Aluxian/huginn,valeriosouza/huginn,valeriosouza/huginn,flagsoft/huginn,mikalauskas/huginn,brianpetro/huginn,dobtco/huginn,MadBomber/huginn,albertsun/huginn,megaxox/huginn,materliu/huginn,mirko314/huginn,askl56/huginn,gautamkrishnar/huginn,younata/huginn,pssaravanan/huginn,kyroskoh/huginn,megaxox/huginn,c24b/huginn,huginn/huginn,niravaga/huginn,omniscopeio/huginn,satishgoda/huginn,djolivier/huginn,pssaravanan/huginn,deanishe/huginn,whicheverpeady/huginn,c24b/huginn,KentFujii/huginn,Aluxian/huginn,cpretzer/huginn,mindvalley/huginn,niravaga/huginn,run-project/huginn,stephenanthony/huginn,virtadpt/huginn,Ishfal/huginn,cantonic/huginn,CodeHunter2006/huginn,c24b/huginn,satishgoda/huginn,angelabier1/huginn,askl56/huginn,wxdublin/huginn,dnjo/huginn,run-project/huginn,azati/huginn,CodeHunter2006/huginn,shirshendu/huginn,purposeindustries/huginn,swimclan/huginn,bartoszkopinski/huginn,madflow/huginn,KentFujii/huginn,darrencauthon/huginn,MOZGIII/huginn,dsander/huginn,mirko314/huginn,MadBomber/huginn,KentFujii/huginn,cantonic/huginn,breandan/huginn,albertsun/huginn,run-project/huginn,brianpetro/huginn,angelabier1/huginn,Ishfal/huginn,mathias/huginn,bartoszkopinski/huginn,cpretzer/huginn,TildeWill/huginn,badrul/huginn,duke-libraries/huginn,megaxox/huginn,dnjo/huginn-spotify-linker,shirshendu/huginn,gautamkrishnar/huginn,dobtco/huginn,mindvalley/huginn,bencornelis/huginn,askl56/huginn,younata/huginn,VelocityGrowth/huginn,brianpetro/huginn,angelabier1/huginn,mathias/huginn,darrencauthon/huginn,strugee/huginn,rasata/huginn,madflow/huginn,djolivier/huginn,dsander/huginn,strugee/huginn,duke-libraries/huginn,purposeindustries/huginn,dnjo/huginn,cpretzer/huginn,armuk/huginn,cantino/huginn,ianblenke/huginn,huginn/huginn,naiyt/huginn,deanishe/huginn,johnleeming/huginn,huginn/huginn,AdrianoCahete/huginn,madflow/huginn,creativepsyco/huginn,swimclan/huginn,whicheverpeady/huginn,MOZGIII/huginn,materliu/huginn,dnjo/huginn,jezcope/huginn,purposeindustries/huginn,virtadpt/huginn,wxdublin/huginn,swimclan/huginn,strugee/huginn,breandan/huginn,gautamkrishnar/huginn,bencornelis/huginn,jezcope/huginn,ahmadassaf/IFTTT-Plus,marcusgadbem/huginn,marcusgadbem/huginn