XWiki Syntax 2.0 should ignore spaces before any "standalone block" syntax

for example

<SPACE>* list item

render a list but

<SPACE>| cell1 | cell2

does not render a table because of the spaces before the first '|'

The support for leading spaces should be a general rule for standalone blocks (header, lists, tables, macros, verbatim, etc.)

See http://markmail.org/message/3vk74efhzorogmhf