In **dev** branch bug in relative positioning

[hchauvet]

When a first element position is set using "right()", "center()" or "bottom()" and that the second element position is relative to the first one their is a bug (left and right are inverted)

Reproduce the bug:

t = text('test align on right', x=right(0.95), y='center')
t2 = text('not aligned on right of t', x=t.right)