added send_message

Not sure about the sending message and the idea of an env queue. In
receiving message, we need to be able to access the msg queue of the
current process. Let me know what you think
Merge branch 'master' of https://github.com/edinkha/OSKernel
Revert "Merge branch 'master' of https://github.com/edinkha/OSKernel"

This reverts commit a23caf49334fe90a5c15b915c9626c8fbf1e02d4, reversing
changes made to d5d1c946e399a7f4182ff5eb25ff33a2bd51f9c4.