use PACEE to show page loading progress bar, case #15
replace background hex with pre-defined variable, case #15
load pace.min.js and pace.css as soon as possible, case #15
remove redundant img and space, case #15
fix wrong pace plugin path, case #15
move pace's external js/css to internal to reduce http requests, case #15
only use inline style and pace.min.js external, case #15
Finish #15/loading-progress-bar