added reschedule callback interface.
added frame work for ftp.
adding files ported from wget.

Not finished.
compiles now.
..
can log in to ftp now.
connect/auth/size/rest passed.
adding data connection, not finished.
..
usable...
...
enabled option to show metadta.
added function to hash tables: dump and parse.

this can be used to store all key/value pairs in metadata.
dumping hash_table to buffer, not completed yet!
Use hash table to record url/user/passwd/xxx.
removed debug logs.
Merge branch 'dev' -- Added support to FTP.