Fix PowerShell script PATH variable escaping (#68)

- Escape $PATH variable properly to generate literal $ in bash export command
- Prevents PowerShell from trying to interpret $PATH as PowerShell variable

Author: Aaronontheweb

install.ps1

@@ -163,7 +163,7 @@ try {
                                elseif (Test-Path ~/.bashrc) { "~/.bashrc" } 
                                else { "~/.profile" }
 
-                $PathLine = "export PATH=`"$InstallPath:`${PATH}`""
+                $PathLine = "export PATH=`"$InstallPath:\`$PATH`""
 
                 if (-not (Get-Content $ShellProfile -ErrorAction SilentlyContinue | Select-String -Pattern [regex]::Escape($InstallPath))) {
                     Add-Content -Path $ShellProfile -Value $PathLine