TSS handling.
Adding default tss file as an example.
copy default.tss
moved the location of the default tss file.
StyledSquareTree is a new Mesquite tree form that hasn't been included yet, so not all features will be reflected.
Put in placeholders for all canvas/tree/scale properties specified in the TSS spec.
changed copyfile to copy.
deleted unimplemented scale properties
Moved unnecessary TSS-specific constants to TSSHandler.java.
command "editingTreeWindow" uses stored trees, which is what we want.
updated build.xml
Merge branch 'TSS_handler' of https://github.com/daisieh/nexml.java into daisieh-TSS_handler
Merge branch 'TSS_handler' of https://github.com/daisieh/nexml.java into daisieh-TSS_handler