Add Filter-String, Write-Message and Get-Nuget to psbuild

[sayedihashimi]

I've used the functions below on several projects where psbuild is used. It would be easier to add this to the psbuild.psm1 directly.

Note: we should investigate if the names of the functions below are what we want to use

function Filter-String{
[cmdletbinding()]
    param(
        [Parameter(Position=0,Mandatory=$true,ValueFromPipeline=$true)]
        [string[]]$message
    )
    process{
        foreach($msg in $message){
            if($nugetApiKey){
                $msg = $msg.Replace($nugetApiKey,'REMOVED-FROM-LOG')
            }

            $msg
        }
    }
}

function Write-Message{
    [cmdletbinding()]
    param(
        [Parameter(Position=0,Mandatory=$true,ValueFromPipeline=$true)]
        [string[]]$message
    )
    process{
        Filter-String -message $message | Write-Verbose
    }
}

<#
.SYNOPSIS
    If nuget is in the tools
    folder then it will be downloaded there.
#>
function Get-Nuget{
    [cmdletbinding()]
    param(
        $toolsDir = ("$env:LOCALAPPDATA\LigerShark\tools\"),
        $nugetDownloadUrl = 'http://nuget.org/nuget.exe'
    )
    process{
        $nugetDestPath = Join-Path -Path $toolsDir -ChildPath nuget.exe

        if(!(Test-Path $nugetDestPath)){
            $nugetDir = ([System.IO.Path]::GetDirectoryName($nugetDestPath))
            if(!(Test-Path $nugetDir)){
                New-Item -Path $nugetDir -ItemType Directory | Out-Null
            }

            'Downloading nuget.exe' | Write-Message
            (New-Object System.Net.WebClient).DownloadFile($nugetDownloadUrl, $nugetDestPath)

            # double check that is was written to disk
            if(!(Test-Path $nugetDestPath)){
                throw 'unable to download nuget'
            }
        }

        # return the path of the file
        $nugetDestPath
    }
}

[sayedihashimi]

Get-FilteredString was added a while back and Get-NuGet is available because nuget-powershell is imported.