Include if-else and if-elseif-else mutations in blocks drawer
Include if-else and if-elseif-else mutations in blocks drawer

Resolves #1975

marksherman/appinventor-sources,ewpatton/appinventor-sources,jisqyv/appinventor-sources,mit-dig/punya,kkashi01/appinventor-sources,jisqyv/appinventor-sources,jisqyv/appinventor-sources,marksherman/appinventor-sources,kkashi01/appinventor-sources,barreeeiroo/appinventor-sources,josmas/app-inventor,ewpatton/appinventor-sources,ewpatton/appinventor-sources,marksherman/appinventor-sources,ewpatton/appinventor-sources,mit-dig/punya,josmas/app-inventor,puravidaapps/appinventor-sources,ewpatton/appinventor-sources,halatmit/appinventor-sources,mit-cml/appinventor-sources,puravidaapps/appinventor-sources,halatmit/appinventor-sources,kkashi01/appinventor-sources,josmas/app-inventor,kkashi01/appinventor-sources,mit-dig/punya,halatmit/appinventor-sources,mit-cml/appinventor-sources,puravidaapps/appinventor-sources,halatmit/appinventor-sources,jisqyv/appinventor-sources,mit-dig/punya,marksherman/appinventor-sources,puravidaapps/appinventor-sources,josmas/app-inventor,mit-cml/appinventor-sources,kkashi01/appinventor-sources,barreeeiroo/appinventor-sources,halatmit/appinventor-sources,marksherman/appinventor-sources,barreeeiroo/appinventor-sources,marksherman/appinventor-sources,josmas/app-inventor,jisqyv/appinventor-sources,halatmit/appinventor-sources,jisqyv/appinventor-sources,barreeeiroo/appinventor-sources,mit-dig/punya,mit-dig/punya,mit-cml/appinventor-sources,mit-cml/appinventor-sources,puravidaapps/appinventor-sources,mit-cml/appinventor-sources,kkashi01/appinventor-sources,ewpatton/appinventor-sources,barreeeiroo/appinventor-sources,josmas/app-inventor,mit-dig/punya