Now the default for using the SVG tiny profile is false.
Now the default for use native text decoration is true.

Fixed the following issues:

1) Text decoration (underline, strike-out) was not exported.

2) Commit 0a4e9138 (tdf#56467: improve export of formulas to SVG) had a
side effect: all exported text portions have position attributes (x,y)
even if they are on the same line (y_old == y_new): this caused that
underlined text belonging to 2 different `tspan` element was not
underlined by a continuous line but there was a gap where a `tspan`
ended and the next `tspan` started.

3) In commit (tdf#37650: further improvement of svg export)
StartTextShape method is invoked even when positioned characters are
used but the `implWriteText` method always adds a `text` element by
itself so there is no need to call StartTextShape.
The changes for non-positioned characters have been embedded inside the
`WriteTextPortion` method.

Change-Id: Iee0d6a6816dcbd2d97f2fbdf969f012de678604e
Reviewed-on: https://gerrit.libreoffice.org/19672Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jan Holesovsky <kendy@collabora.com>