Correctly interpret dynamic characters marked as prealigned

[recursion-ninja]

When reading in a file that contains dynamic characters and that file is marked as having prealigned data we need to interpret the dynamic characters correctly as static characters.

This involves:

• [x] Checking that all dynamic characters have the same length (if they are not a missing character)

• [x] Expand out the metadata vector by the length of the dynamic character with new static character metadata.

• [x] Expand the character sequences by the length fo the dynamic character with new static character decorations.

[recursion-ninja]

Now correctly handles files marked as prealigned and Nexus files with aligned characters.