New-SSHShellStream $TerminalName should default to `dumb` not `PoshSSHTerm`

[keithga]

All trace logs on my Posh-SSH commands reveal:

tput: unknown terminal "PoshSSHTerm"

This is because the default terminal type defined in Posh-SSH.ps1 for New-SSHShellStream() is defined as "PoshSSHTerm". And becomes the default terminal "Type" passed into whatever linux host we are connecting to. However tehre is no default definition for "PoshSSHTerm" in most linux distros, so tput returns the error above in the Powershell trace commands (start-transcript).

The easy solution is to select -TermnialName 'dumb' when calling the cmdlet New-SSHShellStream, dumb is defined in most Linux Distros (no error message from tput), and won't display any escape characters that confuse powershell.