invenio.ext.menu: listing items on path between entries
invenio.base: added globals.py

* current_blueprint: blueprint containing the requested function.

* current_function: function executed for the current request.
invenio.ext.breadcrumb: created extension
invenio.modules.tags: example usage of breadcrumbs
ext.breadcrumb: fixes and porting
breadcrumbs_map removal WIP
ext.breadcrumbs: cleaning
tags: templates moved to module
templates: templates loading order fix
inveniomanage: fixed import of sqlalchemy
invenio.base.globals: fixed current_blueprint
invenio.ext.breadcrumb: created extension

* Automatized processing of breadcrumbs.
* Decorate blueprint functions with register_breadcrumb to display breadcrumb path.
* Set blueprint-wide breadcrumb base with default_breadcrumb_root.

Signed-off-by: Krzysztof Lis <krzysztof.lis@cern.ch>
example usage of invenio.ext.breadcrumb