Initial Commit

Just need to get vertical piping to work. Also some weird things happen
with signal checking... Oh setjmp
Added LWD feature
Solved the mysterious duplicating process issue

Exiting on failed exec...
Added error messages to calls
Merge branch 'master' of github.com:mks65-dw/shell
Added semicolon acceptance, error handling
Merge branch 'master' of github.com:mks65-dw/shell
Merge branch 'master' of github.com:mks65-dw/shell
Merge branch 'master' of github.com:mks65-dw/shell
Merge branch 'master' of github.com:mks65-dw/shell