get_external_dependencies.sh uses exit 1 on successful completion

[vivekmalneedi]

get_external_dependencies.sh returns with exit code 1 on both error and successful completion

It should instead use exit 0 whenever the script successfully downloads the dependencies or displays the help message

Additionally, line 236 of the readme has build written as b0uild

Thanks

[bchetwynd]

Thanks, Vivek. I will roll it into the next release.