Disable caching for imagemin task (#422)
Disable caching for imagemin task (#422)

StartPolymer/polymer-starter-kit,Jelle-imitto/tools-polymer,LM450N/polymer-starter-kit,FaellCarvalho/Geo-Location,Jelle-imitto/tools-polymer,stephenzsy/charon-frontend,markovuksanovic/polymer-starter-kit,gick/mobile-polymer-starter-2,robdodson/polymer-starter-kit,felixzapata/polymer-starter-kit,Negashev/negash.ru,abdonrd/polymer-starter-kit,gianluka79/First,Ex-ante-Labs/pivot-ahead,RoyKoh/Project-3,JnJSW/dttdata,proplanr/polymer-starter-kit,gick/mobile-polymer-starter-2,alexpaluzzi/polymer-starter-kit,JnJSW/dttdata,Sykkro/penny-web,jdavidagudelo/polymerstarter,natabbotts/blogs.org.uk,SB-Technology-Holdings-International/Water,gick/mobile-polymer-starter-2,RoyKoh/Project-3,trendystore/store,Jelle-imitto/tools-polymer,proplanr/polymer-starter-kit,semafloor/semafloor-test-alpha,StartPolymer/polymer-starter-kit,1001genomes/admixture-map,trendystore/store,Ex-ante-Labs/pivot-ahead,klarkc/polymer-loopback-starter-kit,StartPolymer/polymer-starter-kit-plus,michaetto/f16,SB-Technology-Holdings-International/Water,andrefuller/PolymerTrailerViewer,Negashev/negash.ru,klarkc/polymer-loopback-starter-kit,lordoftheflies/mlm-portal,tecla5/site,stefanoantonel/ecofit,jdavidagudelo/polymerstarter,mtusk/polymer-starter-kit,SB-Technology-Holdings-International/Water,trendystore/store,ragingwind/polymer-starter-kit,gick/reveries-project,Serious-Rage/poligomy,markovuksanovic/polymer-starter-kit,klarkc/polymer-loopback-starter-kit,FaellCarvalho/Geo-Location,LM450N/polymer-starter-kit,abdonrd/polymer-starter-kit,gertcuykens/polymer-starter-kit,anthonybrown/polymer-starter-kit,Jelle-imitto/tools-polymer,stephenzsy/charon-frontend,Sykkro/penny-web,michaetto/f16,flaiker/polymer-starter-kit,bdnorg/tmi,lordoftheflies/mlm-portal,andrefuller/PolymerTrailerViewer,tecla5/site,Serious-Rage/poligomy,stefanoantonel/brainpower,markovuksanovic/polymer-starter-kit,grebett/polymer-starter-kit,SB-Technology-Holdings-International/WateringWebClient,Ex-ante-Labs/shopper.ninja,anthonybrown/polymer-starter-kit,felixzapata/polymer-starter-kit,Ex-ante-Labs/shopper.ninja,RoyKoh/Project-3,SB-Technology-Holdings-International/WateringWebClient,1001genomes/admixture-map,grebett/polymer-starter-kit,flaiker/polymer-starter-kit,bdnorg/tmi,victorgb6/id-questionary,victorgb6/id-questionary,natabbotts/blogs.org.uk,gertcuykens/polymer-starter-kit,victorgb6/id-questionary,Sykkro/penny-web,SB-Technology-Holdings-International/Water,andrefuller/PolymerTrailerViewer,gick/reveries-project,plusCubed/pluscubed-site,Jelle-imitto/tools-polymer,LM450N/polymer-starter-kit,gianluka79/First,stefanoantonel/ecofit,felixzapata/polymer-starter-kit,ragingwind/polymer-starter-kit,FaellCarvalho/Geo-Location,JnJSW/dttdata,semafloor/semafloor-test-alpha,proplanr/polymer-starter-kit,gick/reveries-project,ragingwind/polymer-starter-kit,plusCubed/pluscubed-site,StartPolymer/polymer-starter-kit-plus,SB-Technology-Holdings-International/Water,mtusk/polymer-starter-kit,SB-Technology-Holdings-International/WateringWebClient,stefanoantonel/brainpower,robdodson/polymer-starter-kit,Negashev/negash.ru,alexpaluzzi/polymer-starter-kit,stephenzsy/charon-frontend,alexpaluzzi/polymer-starter-kit,gertcuykens/polymer-starter-kit,michaetto/f16,lordoftheflies/mlm-portal,stefanoantonel/ecofit,SB-Technology-Holdings-International/WateringWebClient,gianluka79/First,semafloor/semafloor-test-alpha,grebett/polymer-starter-kit,Serious-Rage/poligomy