fix #752 Optimisation on the JsonSerializer, after #750
fix #751 pixel-percentage conversions broken

Conversions between pixels and percents were working only in IE8-
due to a mistake in 107507a30d0407e46bcbf6dea3cf31ee28c43928.
feat #718 option to use `referenceId` in `@touch:Dialog`

Close #718. Close #726.