Add a getHostname to system
It is better to abstract how we retrieve the hostname than to access
it directly (see also getAppVersion).
# use glob syntax.
syntax: glob
*.pyc
*.zip
*~
.project
.pydevproject
app.yaml
build
tests/coverageResults
*,cover
tests/.coverage
*.git
*.egg-info
eggs
parts
.installed.cfg
bin
develop-eggs
.gitignore
.DS_Store
.settings