Reduced the number of SQL queries used on the bug summary page.
The following changes were made:

• Use only one query to get bugnote count and the last_modified date
• Add filtered bug rows to bug cache (new function bug_add_to_cache() )
• Cache attachment count for all bugs

This reduces the query count from about 300 to about 120 when 100 bugs are displayed with file attachment indicator and bugnote count displayed in the list and should dramatically speed up page execution at that point.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2554 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9