Add device sector size to partition object

The device sector size is needed in all calculations that convert
between sectors and bytes.  The device sector_size is included in
the partition object because this object is used to contain
operation information in addition to actual partitions and
unallocated space.  A second option was considered to pass the
device object to many methods, but this was considered a much
larger task that might not provide significant gains in
maintainability.

include/Partition.h

@@ -116,6 +116,8 @@ public:
 	bool strict ;		//Indicator if start and end sectors must stay unchanged
 	bool strict_start ;	//Indicator if start sector must stay unchanged
 
+	Byte_Value sector_size ;  //Sector size of the disk device needed for converting to/from sectors and bytes.
+
 private:
 	void sort_paths_and_remove_duplicates() ;
 

src/Partition.cc

@@ -43,6 +43,7 @@ void Partition::Reset()
 	label .clear() ;
 	uuid .clear() ;
 	partition_number = sector_start = sector_end = sectors_used = sectors_unused = -1;
+	sector_size = 0 ;
 	color .set( "black" ) ;
 	inside_extended = busy = strict = strict_start = false ;
 	logicals .clear() ;