These common methods allow to manage UI and DM classes component, change
internal progress meter identifier, speed animation, and many other little tasks.
The HTML_Progress_Observer class provides an implementation
of the observer pattern.
In the content of the HTML_Progress package, it provides a mechanism by which you can
examine special event as it is happened. This allows the implementation of special behavior.
Default mathematical model (HTML_Progress_DM class) handles
a common progress bar with a minimum and initial value sets to 0, a maximum set to 100,
and an increment set to 1.
The HTML_Progress_UI class provides methods for
html code display and element attributes handling.
You can overload it with HTML_Progress::setUI method.
