Improved diagnostic output: when the build fails because a package cannot be cloned into the build drive, it says which package and the repo source and destination. Improved caching logic, so that it doesn't depend on network availability as much. Improved indentation.

@echo off
setlocal
if not defined HELIUM_HOME set HELIUM_HOME=%~dp0..\..\..\..\helium
echo %HELIUM_HOME%
rem call ..\..\build\env.bat
call %HELIUM_HOME%\hlm.bat %*
endlocal