When saving the file odf/odp/114096.odp from calligratests invalid xml is generated:

[11:37:25]: [odf/odp/114096.odp] INVALIDSTYLESXML:
(unknown file): 62 error: value of attribute "svg:x2" is invalid; must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)%" or must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)((cm)|(mm)|(in)|(pt)|(pc)|(px))"
(unknown file):62: error: value of attribute "svg:y1" is invalid; must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)%" or must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)((cm)|(mm)|(in)|(pt)|(pc)|(px))"
(unknown file):65: error: value of attribute "svg:x2" is invalid; must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)%" or must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)((cm)|(mm)|(in)|(pt)|(pc)|(px))"
(unknown file):65: error: value of attribute "svg:y1" is invalid; must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)%" or must be a string matching the regular expression "-?([0-9]+(\.[0-9]*)?|\.[0-9]+)((cm)|(mm)|(in)|(pt)|(pc)|(px))"

The problem is that the gradient attributes are saved like:

<svg:linearGradient draw:name="gradient3" svg:spreadMethod="pad" svg:x1="100%" svg:x2="-6.66134e-14%" svg:y1="5.55112e-14%" svg:y2="100%">
    <svg:stop svg:offset="0" svg:stop-color="#cc3300"/>
    <svg:stop svg:offset="1" svg:stop-color="#c7a309"/>
</svg:linearGradient>

however e-14 is not alloed in the value for precent.

This patch adds a new function to add percent attributes that takes care of using the correct format.