Fixed ocp-build init
Added linking of class methods
Added support for multiple bindings in Trie

it's possible to have the same path bound to a type, a value and a class...
Fixed obscuring of values/types/classes with the same name
Filtering out implicit class-types ('#name')
Filtering out hidden values before display
Factorised the unique_subdirs function, useful in the library
Added a test file

Tests are manual for now. Use
```
ocamlc -bin-annot -c test/test.mli
```

then run ocp-index/ocp-browser with `-I test` and complete on Test.