Search, Warnings, Widgets, Excerpts

* Search: search implementation now explicitly redirects to the page
marked as the search page, instead of showing the search results in any
page
* Warnings; less warning when wp_debug is set to true (strato)
* Widgets now can use the nxs_widgets_getinitialvalues() functie to
prevent warnings when rendering html
* Removed excerpts from system (phase 2)