add encode64 and decode64 for shell

fetch:Sendak jane$ echo 'asdkljasddsfkl;jsfdgl;kdsfjg' | perl bin/pl/en64.pl
YXNka2xqYXNkZHNma2w7anNmZGdsO2tkc2ZqZwo=

fetch:Sendak jane$ echo 'asdkljasddsfkl;jsfdgl;kdsfjg' | perl bin/pl/en64.pl  | perl bin/pl/de64.pl
asdkljasddsfkl;jsfdgl;kdsfjg