Added Get-LibSymbols

Get-LibSymbols parses Microsoft .lib files and displays decorated and
undecorated symbols.
Fixed minor logic bug in C type undecorated symbols
Added exfil script synopses to README.md

Descriptions for Invoke-NinjaCopy and Invoke-Mimikatz were added to the
readme.
Modified license verbiage
Slight clarification to license statement
Added a usage tip

Added a one-liner for PSv3 that will remove the annoying warnings that
are displayed when importing scripts downloaded from the Internet.
Updated usage tip
Fix for hostfiles option in powershell 2