Add docstrings for agent.py

Does what it says.

Partial-Bug: 1367915

Change-Id: If2617f30c75c4a844c20a60afa41330daf84053a
Preserve environment variables when doing sudo

This commit adds the '-E' option for all the sudo commands
in build script of agent which causes it to preserve environment
variables.

Change-Id: Ic3fbc4ee8189cc82ef99359bf61eef33dae40a5a
Closes-Bug: 1371418
Add support to build iso image

This script adds support to build iso image from the given
kernel and ramdisk

Change-Id: I15dd8b8663af15b4194299986792ad8e6487508b
Implements: blueprint ilo-virtualmedia-ipa
Add docstrings for api/ tree

Does what it says.

Partial-Bug 1367915

Change-Id: Id1a718d652f6d98e6acb1d667f42d9c3cc82aef5
Delete unused method get_agent_mac_address()

Does what it says.

Change-Id: I01e20e3a1e7317c17da6fc04ee0b0a672cf8247b
Refactor image writing

What it says
Add VHD Writer

What it says.
Start ironic-python-agent in debug

Just for debugging.