Added SQL SERVER 2008 R2 compatibility (preserving MySQL compatibility). We tested all features with REDMINE 2.3.3 + SQL SERVER 2008 R2, and with SQL SERVER 2012.

Now this plugin can be used with SQL SERVER 2008 R2 (and versions above).
Substitution of tag "labelled_form_for" to "labelled_tabular_form_for" in view files for REDMINE 2.3.3 compatibility.
Spanish translation
PT-BR translation corrections