Add error reporting to generate_sample.sh on import failure.

Currently tools/conf/generate_sample.sh collect options from project
modules by importing each module and looking at it's global variables
for instances of classes derived from cfg.Opt (or lists of such
instances). Sometimes this import can fail due to various reasons,
cfg.DuplicateOptError for example. And if import fails no options
from imported module written to sample config file. Error reporting
will at least warn user that some of options didn't get into sample
config.

Change-Id: I831464b1c1575c106d866a936a50ec74b2d44e59
Fixes: bug #1182611
Fix AttributeError typo

Fixes Bug LP #1186566

Change-Id: I8211d365c4d3532cd6ffc3b3041661ff6b9e637f
python3: Introduce py33 to tox.ini

Introduce py33 to tox.ini to make testing
easier with python3.

Change-Id: I351fa475deffd75201e20e3629af6ed018b9ac7c
Signed-off-by: Chuck Short <chuck.short@canonical.com>
Merge "Add error reporting to generate_sample.sh on import failure."
Merge "Fix AttributeError typo"
Merge "python3: Introduce py33 to tox.ini"