[oe] How do i get py-smbus include in image

[Ed Nelson]

I am trying to use py-smbus and see that it is included in i2c-tool but 
by default it is not built. It also looks like from the readme file 
under py-smbus that lm-sensors need to be built 1st.

I assume I would add both i2c-tools and lm-sensor to my image recipe as 
follows but is there anything else I need to do to get py-smbus built.

========

#Angstrom base-image with python

require base-image.bb

DEPENDS += "python \
                         python-pyserial \
                         mtd-utils \
                         i2c-tools \
                         lm-sensors \
        "

IMAGE_INSTALL += "python \
                                    python-pyserial \
                                    mtd-utils \
                                    i2c-tools \
                                    lm-sensors \
                                    nano \
              "

export IMAGE_BASENAME = "base-python-image"

========================

Thanks
Ed