Plugin system and machine tags for Shapado

by obvio171 for Marine Biological Laboratory Biodiversity Informatics Group-Encyclopedia of Life Project

The Encyclopedia of Life wants to use Shapado, a FOSS project, as a Q&A system for its database of species. Many of the customizations needed are not of general interest so, to avoid feature creep, this GSoC project intends to create a plugin system for Shapado to allow creation and sharing of features while keeping a clean and solid core. It also intends to implement machine tags as a first plugin, making the EOL-Shapado integration more immediately possible.