update xe-core 1.7.5.3

updated xe-core 1.7.5.3.

to retain same original format. i only extarct js and css and did'nt tounch it.

if minified version is not exist, it means, combined minifeid version is exist.

ex) xe.min js = common.js +  js_app.js + xml_handler.js +xml_js_filter.js (in /commons/js folder).

this project is simular to wordpress jet pack.