add WKT support

[tschaub]

Here's an example:  http://dev.openlayers.org/sandbox/tschaub/wkt/examples/wkt.html

The following patch includes the new format, tests, and the above example. If this makes it in, I'll make a multi-purpose example that demonstrates all vector formats.

Also, I think I'll propose next that geometry.toString be changed simply to

return OpenLayers.Format.WKT.prototype.write(this);

This would mean that all geometries would require Format/WKT.js - but it seems like a pretty slick solution. I'll leave that for another patch.

Note that we already have one user who is using this to insert feaatues into an Oracle db with ArcSDE.

[tschaub]

read/write support for WKT

[tschaub]

I'll happily commit if this passes review.

[sderle]

looks great! nice work. please apply.

[crschmidt]

Please be aware that the vector layer renderers use 'toString' to get a value which they use for printing points. If the toString of geometries changes, there needs to be another value which the renderers can use.

[crschmidt]

I'm a doofus. They use toShortString, not toString. I'm in favor of making WKT the default encoding of geometry objects as strings.

[tschaub]

committed in r2942