adopt to renamed "struct metadata::TaskContext" in "tools/metadata_orogen"

see also https://github.com/rock-core/tools-orogen_metadata/pull/2

Signed-off-by: Martin Zenzes <martin.zenzes@dfki.de>
Merge pull request #3 from marvin2k/rename_struct_Component

adopt to renamed "struct metadata::TaskContext"
register include metadata for standard C++ types as well

The include metadata is generated at loading time now. By calling
add_standard_cxx_types we do "load" types but we are not registering
the orogen_include metadata required by orogen (this is a typelib
method). Do so explicitely