Moved Twig cache config setting
Improved constant 'ROOT_DIR' definition
Added type-hint to constructor of 'Zepto'
Removed an errant 'var_dump() and die()'
Updated 'content/sub/index.md' and 'content/sub/page.md' to be shorter for testing
Renamed constant to 'ROOT_DIR' in 'tests/Bootstrap.php'
Added tests for 'FileLoader'
Generated test class for 'Router'
Removed test class for 'Zepto' temporarily