Implemented table alignment class as an optional configuration option. Using the align attribute if not configured.
Added protection attributes.
Added Public API and Versionning Policy to readme file.
Added extra attribute block for links and images.
Merge branch 'extra' into lib-protected

Conflicts:
	Michelf/Markdown.php
	Readme.md
Fixed readme to include information about beta 5.
Added protected visibility attribute to a few new functions coming from the extra branch.
Updates to readme file.
Fix for issue 72.
Merge branch 'extra' into lib

Conflicts:
	Readme.md
Merge branch 'lib-protected' into lib

Conflicts:
	Readme.md
Wrong initialization of the in_anchor member variable.
Merge branch 'master' into extra
Merge branch 'extra' into lib