Initial implementation of MinimalKB

Supports all the dummy methods required by Dialogs
Added a SQLite store. Only add/retract are supported for now
Initial implementation of find

Currently support only statements where only the bound variable appears
Add support for loading triples from a file

Currently, only a list of 's p o', one per line
Added a commonsense ontology, based on ORO

It is actually ORO grabbed from kb.openrobots.org, with a couple of meta statements
stripped out.
Marking non standard API methods as @compat, add findmpe as alias for find, improve debug msgs
Colorize log output
Added a first set of unit-tests
Extended API: clear, lookup, about, exist, add, retract

While here, improve robustness to ill-formed input, extended support
of models (in the find queries)
Moved the SQLite code in a separate file
Updated README