PECL-ssh2 :: new wrapper for libssh2_channel_subsystem

This is essentially the first half of what needs to be done to add full subsystem capability. I copied the code for ssh2_shell, added the extra string argument, and changed the call in the wrapper from libssh2_channel_shell to libssh2_channel_subsystem. The missing part is fopen url handler, since this is my first time messing with a php extension and was completely lost looking at the ssh2.shell url handler code. --Burke

Attachment: [text/x-patch] pecl-ssh2-subsystem.patch