Blender Git Loki

Cleanup: clarification of 'name' in BKE_idtype functions

The 'name' parameter of `BKE_idtype_idcode_from_name()`, and the `str`
parameter of `idtype_get_info_from_name()`, are expected to be the
'user visible name' of an `IDTypeInfo` struct. This is made clearer in
the code by renaming those parameters to `idtype_name` and mentioning
it in the documentation of the `BKE_idtype_idcode_from_name()`
function.

Differential Revision: https://developer.blender.org/D7317