perview video and links
当前为
support chrome 72
20181006 change source order
20180927 add r18 source, need manual code change
20180922 preview source change to erovi, much better
20180920 insert position change
20180911 search url change, more preview from r18
20180603 prontv turns non-free, use google instead
20180420 first ten links, remove duplicates
20180416 fetch from pron.tv
20180203 now work on latest centbrowser
20180124 use low/med if no high quality
