Add char type to model and value layer

[ywei]

Add the character type class to the model module and the layer module. Character addition/subtraction operations are not allowed.

[ywei]

Char type added during last meeting.

[zirkel]

Character type is represented at the model and value layer. At the symbolic layer, a character is represented as an integer. The value layer does this conversion.

[Stephen Siegel]

Still need to implement arrayLiteralExpression, characterLiteralExpression, and recordLiteralExpression in ModelFactory.

[zirkel]

arrayLiteralExpression and characterLiteralExpression are implemented. In order to create a literal expression from a record, I need the type of the record. However, recordLiteralExpression only takes an array of the components as an argument. This is not enough information to construct a record type, as that also requires the name, fieldNames, and dimensionExpressions. Is it ok to change recordLiteralExpression to take these arguments?

[Stephen Siegel]

How about make the record type an argument to the method, i.e., change

	LiteralExpressionIF recordLiteralExpression(LiteralExpressionIF[] components);

to

	LiteralExpressionIF recordLiteralExpression(RecordTypeIF type, LiteralExpressionIF[] components);

We need to know from the user of this module (front end, i.e., Yi) if this will work for him---will you be able to figure out the record type of the record literal?

[zirkel]

Implemented.