B.2.1.12 Element Connectivity

sectionread	Get infos about a given section
	`return-tuple=`sectionread`(base-id:I,zone-id:I,section-id:I)`
	$\rightarrow$ Returns a tuple containing 'name:S' of the section, its 'type:I''start:I' and 'end:I', 'last-bnd-index:I', 'parent-flag:I'.
nsections	Get lower range index
	`section-index:I=`nsections`(base-id:I,zone-id:I)`
	$\rightarrow$ The lower range is (imin, jmin, kmin)
elementsread	Get elements of a section
	`(elements:A,parents:A)=`elementsread`(base-id:I,zone-id:I,section-id:I)`
	$\rightarrow$ Returns two arrays of I
sectionwrite	Write a section
	`section-id=`sectionwrite`(base-id:I,zone-id:I,section-name:S,args...)`
	$\rightarrow$ The trailing args are the 'type:I' of the section elementsthe 'start:I' and 'end:I' indices, 'last-bnd-index:I'index and at last the 'elements:A' array itself (of type 'type).
elementdatasize	Get the number of elements for this section
	`number:I=`elementdatasize`(base-id:I,zone-id:I,section-id:I)`
	$\rightarrow$ See 'section-write'
parentdatawrite	Write the parent data in a section
	`None=`parentdatawrite`(base-id:I,zone-id:I,section-id:I,parent-data:A)`
	$\rightarrow$ No return
npe	Get the number of nodes for an element type
	`number:I=`npe`(element-type:I)`
	$\rightarrow$ element-type is an enumerate.