Improved publishing of per layer styles for GetCapabilities requests as
well as handling of STYLE parameter for GetMap and GetFeatureInfo
requests according to discussion at
https://github.com/mapnik/OGCServer/issues/29
Removed duplicate style 'default' from capabilities document for
multi-style layers having a regular style named 'default'.
Added unit tests and mapfile for style improvements.
Added namespace '{http://www.opengis.net/wms}' to XPath checks of
capabilities document for WMS 1.1.1 as well.
Removed emission of predefined abstract text for regular styles named
'default' of single-style layers.
Removed XML namespace from 'Abstract' tag.
Removed odd blank line.
Removed namespace for 1.1.1 queries again. WMS 1.1.1 capabilities
document no longer has a default namespace (was fixed by
f55dc2bd21cccf5c2d16020dbb119402b296df99).
Merge pull request #30 from cklein05/style-improvements

Style improvements