Add wmts-capabilities example
Use correct namespaceURI for WGS84BoundingBox reader

(closes #356)
Add new equivalent projections

for both EPSG:4326 and EPSG:3857.
Fix wmts-capabilities example

the parsing of the wmts getCapabilities document require proj4js.

Also initialize common ol3 projections with ol.projection.addCommonProjections
so that it won't try to get EPSG:3857 from proj4js.
The same projection can be added more than once

So that addCommonProjections can be safely called in our examples.
Add exportSymbol for ol.projection.addCommonProjections
Update social links in wmts-capabilities example
Merge pull request #356 from bbinet/issue-356

Can't parse http://maps.wien.gv.at/wmts/1.0.0/WMTSCapabilities.xml