This change means we no longer need to manually update these files when
Isabelle incorporates new unicode symbols. In particular, these translators
will automatically gain support for symbols like "\<longlonglongrightarrow>"
when we move to Isabelle 2016.
When streaming a large theory through these scripts, doing string replacements
line-by-line and repeated dictionary lookups become a significant performance
overhead. Relevant observable functionality should be unaffected by this
change.
Matthew Brecknell
Corey Richardson
Matthew Fernandez
Gerwin Klein