Added -help switch to psake.ps1 instead of psake-help.ps1 script

Simplificated psake.cmd because of that (also removed some ifs that detected if help should be displayed, because they for example make it impossible to call task with name "help")

psake.cmd

@@ -1,15 +1,11 @@
 @echo off
 
-SET DIR=%~dp0%
-
-if '%1'=='/?' goto usage
-if '%1'=='-?' goto usage
-if '%1'=='?' goto usage
-if '%1'=='/help' goto usage
-if '%1'=='help' goto usage
-
-powershell -NoProfile -ExecutionPolicy Bypass -Command "& '%DIR%psake.ps1' %*; if ($psake.build_success -eq $false) { exit 1 } else { exit 0 }"
+if '%1'=='/?' goto help
+if '%1'=='-help' goto help
+if '%1'=='-h' goto help
 
+powershell -NoProfile -ExecutionPolicy Bypass -Command "& '%~dp0\psake.ps1' %*; if ($psake.build_success -eq $false) { exit 1 } else { exit 0 }"
 goto :eof
-:usage
-powershell -NoProfile -ExecutionPolicy Bypass -Command "& '%DIR%psake-help.ps1'"
+
+:help
+powershell -NoProfile -ExecutionPolicy Bypass -Command "& '%~dp0\psake.ps1' -help"

psake.ps1

@@ -18,14 +18,21 @@ param(
     [Parameter(Position=5, Mandatory=0)]
     [System.Collections.Hashtable]$properties = @{},
     [Parameter(Position=6, Mandatory=0)]
-    [string]$scriptPath = $(Split-Path -parent $MyInvocation.MyCommand.path),
+    [switch]$nologo = $false,
     [Parameter(Position=7, Mandatory=0)]
-    [switch]$nologo = $false
+    [switch]$help = $false,
+    [Parameter(Position=8, Mandatory=0)]
+    [string]$scriptPath = $(Split-Path -parent $MyInvocation.MyCommand.path)
 )
 
 # '[p]sake' is the same as 'psake' but $Error is not polluted
 remove-module [p]sake
 import-module (join-path $scriptPath psake.psm1)
+if ($help) {
+  Get-Help Invoke-psake -full
+  return
+}
+
 if (-not(test-path $buildFile)) {
     $absoluteBuildFile = (join-path $scriptPath $buildFile)
     if (test-path $absoluteBuildFile)	{