#248 nexml export: NEXUS-specific syntax in matrix

[Mark Holder]

Similar to the curly-brace bug ( https://sourceforge.net/p/treebase/bugs/245/ ) but this refers to other NEXUS syntax such as a "." I think the dots are probably from Mathchar="." imports. Some files have lots of colons. I"m not sure where they are coming from (could also be matchchar examples).
See http://treebase.org/treebase-web/search/downloadAStudy.html?id=1029&format=nexml

Other IDs: S1029 S10386 S10997 S11363 S1329 S1348 S1649 S1654 S1948 S2100 S230 S264 S320 S338 S352 S361 S648 S681 S742 S765 S792 S794 S925