Add ODB:C++ Object-Relational Mapping(ORM)

ODB is an open-source, cross-platform, and cross-database
object-relational mapping (ORM) system for C++.

Now just add ODB compiler, the common runtime library(libodb) and odb sqlite
runtime library.
Can a test be added to do something more substantial then e.g. `--version` or `--help`? See `cmake.rb` for an example of an application formula with a good test and `tinyxml2.rb` for an example of a library formula with a good test. Thanks!