Remove multiple tabs for phylogenetic tree with MSA Editor

I think we should not support multiple trees with MSA editor, because this feature creating many bugs and problems and don't have any worth for end users.

Example one of bugs:
1. Open COI.aln from samples
2. Build 3 different trees with different algorithms
3. Try to change alignment, then you will see dialog "Alignment Modification Confirmation"
4. Click 'Cancel'.
Expected state: Alignment changes were reverted.
Current state: Dialog "Alignment Modification Confirmation" was shown many times.