Nyagua 2.1

Today I've started the works on next (2.1) Nyagua release.

Some items in WISH list are:
- Interface improvements
- Search filter
- Nutrients composition calculators
- Plugins engine
- Default dates on input
- DB maintenance functions
- Events scheduler

NOT everything will be implemented in this version and some other items may be added to list at development time. So suggestions and criticism are welcome...