Bug 5962 - unable to execute prepared statement from Webfocus, with "?cachePrepStmts=true&useServerPrepStmts=true"

Reset the in_use flag in prepared stmt execute function to let prepared stmt execute again in IDB.
Bug 6113 - Wrong result when using analytic function on a view

Fixed fix_fields functions for window function items in item_window_function.cc.
Merge remote branch 'origin/develop' into feature/MySQL-5.6