Minor improvements in comments and comments format.

Fixed bug: missing $variables['head'] = drupal_get_html_head(); in pinned_site_preprocess_page (patch from attiks).
Fixed typo: 'tag' should be 'tab' in the option array of Window Type selectbox on static task edit page (patch from attiks).
Removed $Id$ from all files.

Added cutting off HTML tags and replacing double quotes with single quotes for META tag content string.
Added escaping of double quotes and cutting off HTML tags for some javascript functions parameters.
Added filtering of output urls through check_url() function.
Changed description of the project and some form fields.