Misc changes and fixes.

AsynCoro (scheduler) earlier had 'terminate' method. This is now separated
into 'finish' and 'kill' methods; 'finish' waits for all non-daemon
coroutines to finish before shutting down whereas 'kill' forcefully
terminates non-daemon coroutines before shutting down.

'dest_path_prefix' keyword argument to AsynCoro in disasyncoro module has
been renamed to 'dest_path', and 'dest_path' keyword argument to 'send_file'
and 'del_file' methods has been renamed to 'dir'.

'discoro' module (distributed/parallel computing framework similar to
dispy project) now has '0' as default value for '-c' option (number of
processors to use), so by default discoro uses all processors to run servers.
'-n' option to give IP address/host name in earlier version has been renamed
to '-i' and now '-n' option can be used to give symbolic name for the servers.
This name is appended with hyphen followed by processor number (starting with 0)
when AsynCoro is created.