Vertical Alignment is serialized as integer, load_map() can't parse

[artemp]

serialized output of 'save_map()' gives:

{{{
<Style name="states_shp_labels">



</Style>
}}}

results in failure during 'load_map()':
{{{
UserWarning: Failed to parse attribute 'vertical_alignment'. Expected one of [top, middle, bottom] but got '2' in TextSymbolizer in style 'states_shp_labels'
}}}

[artemp]

[kunitoki] Fixed with r1116

[artemp]

[kunitoki] I'll provide also a test for nose shortly that will check this ticket