re #91 : Improve view rendering pipeline

- Add 'layout' to view context to allow it to be overridden during rendering.
- Use 'data' from context while rendering and unbox first level before passing it to the template layer.
re #91 : Try to find the template file if not type if passed in the identifier.
re #91 : Fix - Do not unregister the loader
re #91 : Refactor KTemplateLocator

- Remove KTemplateLocator::load() method.
- Add support to identifier locator for file type's. If no file type is specific the locator will try to find a file that matches /.../file.format.*
- Allow to pass locator config options when registering a locator
re #91 : Refactor KTemplateEngine

- Add caching support through KTemplateEngineInterface::cache() and isCached() methods. Related config options 'cache', 'cache_path' and 'cache_reload'.
- Pass the template object as a reference to the template engine.
- Allow to pass engine config options when registering an engine.
- Rename KTemplateEngineFactory::getEngines() to getFileTypes()
- Add KTemplateEngineMarkdown
- Add KTemplateEngineTwig
- Add KTemplateFilterMarkdown to handle inline rendering of markdown blocks.
Rename KTemplateAdapter to Template.