Fix pagination bugs

Saving the current page on hard disk was a work around solution because at that moment I didn't had implemented URLs with parameters (routing with regex). This work around is OK if there is just one user surfing on the page:), because if there are more than one, they will influencing what page the other ones is seeing, and that is just wrong.

You can do a little test, open two tabs and navigate with Newer and Older buttons to see the issue.

In \config\route.xml I modified the routes to accept  URLs like /blog/3

<route name="blog page older">
        <path>/blog/{number}</path>
        <path_regexp>/\/blog\/[0-9]+$/i</path_regexp>
        <controllerClass>Blog</controllerClass>
        <action>renderPagination</action>
    </route>

    <route name="blog page newer">
        <path>/blog/{number}</path>
       <controllerClass>Blog</controllerClass>
       <action>renderPagination</action>
    </route>

The regexp is '/\/blog\/[0-9]+$/i' . To avoid a partial match,I appended a $ to the end,  '+' means more than one digit

The BlogModel has two new properties, $page_older and $page_newer which will be set after some verification, should not be lower than 1 and bigger than total number of posts divided by posts per page($per_page) .

        public function setPageNumber($current_page)
        {
            $db=new DBCon;
            $totalPostsNo=$db->countBlogPosts();
            if ($current_page<=1){
           
                $this->page_number=1;
               
            }else if ($current_page>=($totalPostsNo/$this->per_page)){
           
                $this->page_number=$current_page;
                $this->page_older=$current_page -1;
                $this->page_newer=$current_page;
           
            }else{
           
                $this->page_number=$current_page;
                $this->page_older=$current_page -1;
                $this->page_newer=$current_page +1;
            }
           
        }