Remove ol.source.SourceOptions typedef

The ol.source.SourceOptions type is already declared in objectliteral.exports, so it should not be declared in the ol/source/source.js file.
Source option "projection" is a ProjectionLike
Make the generated Export classes accept undefined

We have constructors, like ol.View2D and ol.control.Attribution, whose "options" argument is optional (opt_options). But currently, we cannot do "new ol.View2D()" in uncompiled code that uses an ol3 build compiled in advanced mode. This commit fixes that by changing the generated Export constructors.