This rather large commit refactors the build system to solve a number of
problems:
- Object literal types are now declared in just one place
- There are no more circular dependencies
- There is no need for concealed subclasses in build-standalone mode
When building in standalone mode, you need to include the source in
build/src/external. This declares object literal types as externs so
that their properties are not renamed.
When building with the application, you need to include the source in
build/src/internal. This declares object literal types as typedefs so
that their properties can be renamed and removed.
Note also that ol.MapOptions has been merged into ol.Map, with some
renaming.
