renamed Isar/isar_output.ML to Thy/thy_output.ML;
tuned messages;
Antiquote.scan_arguments (moved from here);
moved ML context stuff to from Context to ML_Context;
use_thy "FP0";
use_thy "FP1";
use_thy "RECDEF";
use_thy "Rules";
use_thy "Sets";
use_thy "Ind";