Clean up segment creation code

Noteworthy changes:
- Adds ability to cancel creating a segment
- Makes segment creation fully the responsibility of the content script, with the popup script buttons simply doing RPC
- Adds types to the Utils.wait function
- Fixes segment timestamps backwards if user marks segment end earlier than the start
- Makes the info menu (in-page popup) workaround clearer and easier to remove in the future.

src/components/SponsorTimeEditComponent.tsx

@@ -344,7 +344,7 @@ class SponsorTimeEditComponent extends React.Component<SponsorTimeEditProps, Spo
         //if it is not a complete sponsor time
         if (sponsorTimes[index].segment.length < 2) {
             //update video player
-            this.props.contentContainer().changeStartSponsorButton(true, false);
+            this.props.contentContainer().updateEditButtonsOnPlayer();
         }
   
         sponsorTimes.splice(index, 1);
@@ -359,7 +359,7 @@ class SponsorTimeEditComponent extends React.Component<SponsorTimeEditProps, Spo
             this.props.submissionNotice.cancel();
             
             //update video player
-            this.props.contentContainer().changeStartSponsorButton(true, false);
+            this.props.contentContainer().updateEditButtonsOnPlayer();
         } else {
             //update display
             this.props.submissionNotice.forceUpdate();