Fix TLS cipher suite random choice not compatible with powershell 2 on windows 7 (#163)
Fix TLS cipher suite random choice not compatible with powershell 2 on windows 7 (#163)

* fix non-ascii filename downloading error.when download files with non-ascii filename,the 'length' part in the packet is the length of string but not bytes,so throw an index-out-of-bounts error

* fix TLS cipher suite random choice not compatible with powershell 2 on windows 7
byt3bl33d3r/Empire,byt3bl33d3r/Empire,byt3bl33d3r/Empire,byt3bl33d3r/Empire,byt3bl33d3r/Empire