Changes

[https://webmademovies.lighthouseapp.com/projects/80723-popcorn-maker/tickets/67-dont-let-a-user-commit-a-blank-field-for-timeline-media-change#ticket-67-7 Bug 67]<br/s>[https://webmademovies.lighthouseapp.com/projects/80723/tickets/157-layer-numbering-issue-on-import Bug 157]<br/>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/254281-muchbasic-confusiontemplate-rehas-apply2-anddescriptions-ok Bug 254]<br/>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/256in-timecodes-should-round-to-1-decimal manifest Bug 256281]<br/s>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/257-add-ds_store-to-gitignore Bug 257]<br/>

 Butter<br/>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/253-layer-numbering-issue-on-import Bug 253]<br/>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/252-dont-let-a-user-commit-a-blank-field-for-timeline-media-change Bug 252]<br/><s>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/256-timecodes-should-round-to-1-decimal Bug 256]</s><br/><s>[https://webmademovies.lighthouseapp.com/projects/65733/tickets/257-add-ds_store-to-gitignore Bug 257]</s><br/><s>[https://webmademovies.lighthouseapp.com/projects/8072365733-butter/tickets/281390-setting-basictrackevent-templateout-hastime-2video-descriptionsduration-incauses-manifest issues Bug 281390]</s><br/>[https://webmademovies.lighthouseapp.com/projects/65733-butter/tickets/434-let-users-move-track-events-together Bug 434]<br/>[https://webmademovies.lighthouseapp.com/projects/65733-butter/tickets/459-fix-the-error-message-given-for-invalid-start-and-end-times-for-track-events Bug 459]<br/><s>[https://webmademovies.lighthouseapp.com/projects/65733-butter/tickets/410-change-all-occurrences-of-const-to-var Bug 410]</s><br/>

* <s>Make it work on iOS</s>