Added sql functions to make connecting more bearable and bind C-c C-p to sql-connect.
Make it possible to send the current PostgreSQL function the sql process.

This introduces sql-beginning-of-defun and sql-end-of-defun functions
that scan for PostgreSQL functions, which are bound the
beginning-of-defun-function and end-of-defun-function in an sql-hook.

This also makes mark-defun work in PostgreSQL files.

Also added an sql-interactive-mode hook to set the prompt regexps for
psql.
Create function to define the token at point with \d.

Also rebind keys for sending paragraphs and buffers and bind
sql-define-token to C-c d.
Added a function to go to a line in the current defun.
Tidy up prompts a little.