Changed version to 0.3 beta

Closes #40,closes #35
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 - Fixes in `SbShell::CanDo()` method
 - Fixed support for flash messages elements (lack of CSS)
 - Adapted login/register actions and views to the theme.acls options
 - Adapted appController file to the theme.acls options
 - Adapted acls model snippets to the theme.acls options
 - Updated default layout (bad description)
 - Toolbars are here again in generated files (!)
 - Created views/common/additionnal_js_css.ctp to handle additionnal CSS and JS in views. Just include this file at the end of your views.
 - Fixed HTML problems in "view" view (remains one, #41)
 - Fixed non-static methods in theme class