SVGHMI: update tests/evghmi to reflect/test latest changes. update generated XSLT.

SVGHMI: multiple non significant changes: doc fixes, modern style access to attributes, enforce double quotes around member name in object literals.

SVGHMI: Changes /CURRENT_PAGE_* behaviour to prevent problem whith multiclient : all clients were switching page when one was jumping.
- now PLC have to prefix page name with "!" to order page switch.
- HMI do not prefix with "!" when jumping, this avoiding looping incidently
- In case of multiple client:
CURRENT_PAGE reflects current page of last client hwo did jump
Setting CURRENT_PAGE with "!" affects all clients simultaneously