Command
QisLib_AddLayer

QisLib_AddLayer

Function:
	int QisLib_AddLayer(int Layer, int DataType);

Inputs:
	Layer: Layer number to be added (unsigned integer).
	DataType: Data type to be added (unsigned integer).

Return:
	success: 0
	failure: one of the following values :

Errors:
	-1: QisLib not initialized.
	-2: The GDSII/OASIS file has not been loaded in memory.
	-3: File open in progress, operation not permitted.

Description:
	- This function adds a layer to the internal database.
	- This function will fail if the GDSII/OASIS file is not loaded into memory or if it
	was not opened as a brand new file using QisLib_NewGDSII/QisLib_NewOASIS.
	- No actual data will be added to the layer. If the datatype is not specified, 0
	would be added as the datatype.
	- Default color and fill for the newly added layer is it's index%6 + 2.
	- Line type is defaulted to 1.