HelloWorld: Add an example of how to get an IP address to bind to

also fix a few typos and reference to slapgrid
slapos.cookbook:wrapper : allow empty lines in environment
version up : groonga 4.0.8 and mroonga 4.08.
version up : HAProxy 1.5.9.
version up eggs.
version up : firefox 34.0.5.
NEO: missing dumps and duplicated default values
Extend NEO recipe to forward parameters for backup cluster
Merge branch 'master' into erp5-cluster

Conflicts:
	stack/erp5/buildout.cfg
NEO: new parameters to setup an external backup cluster