Bug 10480: EXAMPLE plugin with associated template

Bug 10480: EXAMPLE plugin with associated template

The EXAMPLE plugin helps you to create a new style framework plugin by
providing a simple working example and additional documentation for
developers.

Test plan:
[1] Connect the EXAMPLE plugin to one or more fields.
[2] Try the following events:
    a- Focus: If the field is empty, it should put EXAMPLE: into it.
    b- MouseOver: If the field is empty and you move your mouse over it,
       it should have the same effect as Focus.
    c- Change: Edit the field in the editor and tab out of it, the color
       of the text should toggle (randomly) between red, green and blue.
    d- KeyPress: If you edit the field and you type @, it should give AT.
    e- Click: Click on the tag editor. Change the value in the popup.
       If you press OK, the field should be changed.
[3] Would the documentation in the perl script help you to create a plugin?

Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>