Merge from vendor branch TNF:

Merge from vendor branch TNF:
Importing of databases/ruby-arel 1.0.1.

## Abstract ##

Arel is a Relational Algebra for Ruby.

1) simplifies the generation complex of SQL queries
2) adapts to various RDBMS systems

It is intended to be a framework framework; that is, you can build
your own ORM with it, focusing on innovative object and collection
modeling as opposed to database compatibility and query generation.

## Status ##

For the moment, Arel uses ActiveRecord's connection adapters to
connect to the various engines, connection pooling, perform quoting,
and do type conversion. On the horizon is the use of DataObjects
instead.

The long term goal, following both LINQ and DataMapper, is to have
Arel adapt to engines beyond RDBMS, including XML, IMAP, YAML, etc.