Add do-query-dao and do-select-dao working
Add :col-name DAO slot initarg

The sql name of a given DAO class' slot can be set via the :col-name
slot initarg. This value, which is not evaluated, will be passed to
to-sql-name.
Mention :col-name in the DAO docuemntation
Evaluate the arguments passed in via the s-sql:$$ placeholder with cl-postgres:to-sql-string
As per postgresql's convention if the conection host is a string which starts with #\/ connect to a unix socket in that diretory.

To simplify some of the #+ccl and #+sbcl and avoid some code duplication
usocket is always used when connecting to an inet socket.

The change only affects those connections whose host is a string or a
pathname, :unix as a host still works as before (and depends on the
conection time value of *unix-socket-dir*).
Added .gitignore
move transaction code to its own file
add failing tests for logical transactions
implement with-logical-transaction, ensure-transaction, commit-hooks, and abort-hooks
documentation
Merge branch 'master' of https://github.com/enaeher/Postmodern