core render fix

This version introduces multiple enhancements:

fixed undefined method error
added clear cache for templates

Details of additions/deletions below:
--------------------------------------------------------------

Modified:   /Lib/Core/Shell/Helper/Cache.php
            -- Added --
                _clearContentTemplatesCache to remove templates with rendered content
            -- Updated --
                _clearTemplatesCache added remove cached files logic
                run, to handle all remove cache options
                usageHelp, new options description

Modified:   /Lib/Core/Render/View/Abstract.php
            -- Updated --
                render commented _joinTemplates usage

Modified:   /Lib/Core/Shell/etc/config.ini
            -- Modified --
                changed version from 0.1.1 to 0.2.0

Modified:   /Lib/Core/Render/etc/config.ini
            -- Modified --
                changed version from 0.5.0 to 0.5.1