fix(webpack): run incremental build on watch, not any non-prod build
fix(webpack): run incremental build on watch, not any non-prod build

rolandjitsu/ionic-app-scripts,michaelgeorgeattard/ionic-app-scripts,driftyco/ionic-app-scripts,michaelgeorgeattard/ionic-app-scripts,rolandjitsu/ionic-app-scripts,driftyco/ionic-app-scripts,michaelgeorgeattard/ionic-app-scripts,driftyco/ionic-app-scripts,rolandjitsu/ionic-app-scripts