ResourceRef
	Source =>	full path to source file
	Lang =>		language code to use when compiling this resource
	Uids =>		uids for this resource file (if any)
	Hdr =>		anything, indicating that a resource header file is required
	BaseTrg =>	base of target name
	TrgPath =>	target path in the emulated filesystem
	
	Trg =>		target name for this resource, in the form name.Rxx to match LANG

Notes;
TrgPath is filled in at the end for any resource which lacks one
If Lang is not specified, copies of this ResourceRef are made for each of the 
languages specified in the LANG statement.
Trg is constructed from the TrgPath, BaseTrg and Lang information.


BitmapRef
	Source =>	list of bitmap source references, each of the form
		Src =>		full path of BMP file
		ClDepth =>	colour depth as specified in MMP file
	TrgPath =>	target path in the emulated filesystem
	Trg =>		target name for this bitmap as specified in the MMP file
	Hdr =>		anything, indicating that a bitmap header should be generated

AifRef
	Trg =>		target name as specified in the MMP file. Defect: may include directory
	Dir =>		source path
	Resrc =>	resource file name relative to source path
	ClDepth =>	colour depth to apply to bitmap files (design defect!)
	BitMaps =>	list of bitmap files

SourceRef
	SrcPath => full path to source file
	CurFile => full source file name
	BaseTrg => base of source file name