Implemented expandable rows in Vertical mode, with Single/Multi sub-mode

ADDED: Click routine for vertical table native header cells
ADDED: Helper fn to get/set expansion state of tables
ADDED: Naming for rows, possibly not required
FIXED: In single select mode, could not turn off a click, now you can
ADDED: Harness routines to test modes
CHANGED: sTableID to sTableId to normalise across the codebase
CHANGED: setElementVis() to elementVis() so that it is both getter'n'setter