Update sl.js
Update sl.js

months and days in slovenian language are NOT written with capital letters.
pom95/timeline,deenjohn/TimelineJS,ryekee/TimelineJS,stea4lth/TimelineJS,anxintiancai/TimelineJS,CrossLead/TimelineJS,landsurveyorsunited/TimelineJS,LauraHilliger/TimelineJS,landsurveyorsunited/TimelineJS,1modm/TimelineJS,JoaquinSiabra/TimelineJS,pom95/timeline,ycaihua/TimelineJS,anxintiancai/TimelineJS,ryekee/TimelineJS,james-logan/TimelineJS,NUKnightLab/TimelineJS,djaney/TimelineJS,wangjun/TimelineJS,pom95/timeline,zstao/TimelineJS,james-logan/TimelineJS,noikiy/TimelineJS,stea4lth/TimelineJS,angeliaz/TimelineJS,LauraHilliger/TimelineJS,anxintiancai/TimelineJS,stea4lth/TimelineJS,CrossLead/TimelineJS,zstao/TimelineJS,noikiy/TimelineJS,JoaquinSiabra/TimelineJS,deenjohn/TimelineJS,wangjun/TimelineJS,matt-edgedesign/Timelinejs,matt-edgedesign/Timelinejs,ycaihua/TimelineJS,noikiy/TimelineJS,djaney/TimelineJS,cweems/api-timeline-js,djaney/TimelineJS,1modm/TimelineJS,james-logan/TimelineJS,matt-edgedesign/Timelinejs,JoaquinSiabra/TimelineJS,angeliaz/TimelineJS,1modm/TimelineJS,landsurveyorsunited/TimelineJS,NUKnightLab/TimelineJS,cweems/api-timeline-js,ycaihua/TimelineJS,wangjun/TimelineJS,LauraHilliger/TimelineJS,NUKnightLab/TimelineJS,deenjohn/TimelineJS,zstao/TimelineJS,ryekee/TimelineJS