Fixed a bug whereby if there was a gap in the row of signs, an update to the first course would update any subsequent signs as if they belonged to the first display.
For example, 2 Parkour Top Ten displays in a line:

1st 2nd 3rd <space> 1st 2nd 3rd

could have been overwritten as:

1st 2nd 3rd <space> 5th 6th 7th

So, when building a top ten display, if there is no sign to the right of the current sign then the first display ends. This allows 2 or more displays to be placed in a line without the 2nd and subsequent ones being overwritten by an update to the first display.