add path check and pip install

demo/0-download-pdbs.ps1

@@ -1,6 +1,11 @@
-# py -m pip install requests pefile
-
 $r = $PsScriptRoot
+if ((Get-Location).Path -ne $r) {
+	Write-Host "This script must be executed from within $r"
+	Exit
+}
+
+py -m pip install requests pefile
+
 $edrs = "$r\..\helpers\EDRSandblast"
 $eoffs = "$edrs\ExtractOffsets.py"
 $offsets = "$edrs\offsets\"
@@ -14,4 +19,4 @@ py $eoffs ntoskrnl -i $offsets
 py $eoffs fltmgr -i $offsets
 
 mv "$r\NtoskrnlOffsets.csv" $offsets -Force
-mv "$r\FltmgrOffsets.csv" $offsets -Force
+mv "$r\FltmgrOffsets.csv" $offsets -Force