added a new vector dimension check
bugfix in index pattern printout for 2D patterns (parentheses where missing);
improved sectioned index pattern detection (can produce simplier patterns)
minor cosmetic changes in the tank battery model
minor cosmetic changes to the model plug flow and distillation models
initial support for loops which have equations which are not defined for some iterations;
improved detection of relations between dependents of different equation patterns;
new operations: CGAssignOp, CGPriOp, CGLoopIndexedTmpOp, CGTmpDclOp and CGTmpOp;
new tests