Gdb.debug

Closes #69.  Enables launching `gdb` and `gdbserver` either locally, or over SSH.

shell = ssh(host='optiplex', user='user', password='user')
gdb.debug(['/bin/bash'], ssh=shell, exe='/bin/bash')Closes #69.  Enables launching `gdb` and `gdbserver` either locally, or over SSH.


**Example**
```python
shell = ssh(host='optiplex', user='user', password='user')
gdb.debug(['/bin/bash'], ssh=shell, exe='/bin/bash')
```