Replaced 'e.g.' with 'for example'

According to the IBM Style Guide the Latin abbreviation 'e.g.'
should be replaced by 'for example'.

Change-Id: Ie85eec0f028a927a635303f7c13e76fe52a92ff5
Merge "Replaced 'e.g.' with 'for example'"
Hook IPOpt class into the docs

Change-Id: I02b38b89f32db8b03a94467cdf5c6ff1c8865f2b