The abstract functions of database have been made protected and their
names prefixed with '_'.  The database class has been given new static
functions query() and esc(), which call the _query() and _esc() function
from the database instance object.  This change was made to address the
use of db routines from static contexes.  Calls like
`database::get()->query()` which mix static and instance function access
operators, can now be `database::query()`, and all singleton is
abstracted away; the instance's destructor continues to close the db
connection.

Need to remove the NULL return value from fetch_assoc() to fix usages of
count($res) for determining the number of results from a MySQL query.
This NULL return value is returned from mysqli's fetch_assoc() function
to signal no more result rows.

Setup to perform an iteration of development focused on a simpler
implementation and eliminating redundancy in design.

+ Defined interface for Mysql DBMS for Scrott