Improvement in grub options

 * Be more robust when setting GRUB_CMDLINE_LINUX_DEFAULT
 * Stop console from blanking
 * Switch elevator to noop as disks are not real disks and this yields
   better performance.
Fix call to boto get_all_images()
Jessie contains dhcpcd5 instaed of dhcpcd; fixing configuration.
Fix wrong condition in dhcpcd configuration in Jessie.
Merge pull request #118 from rybaktomasz/dhcpcd-unstable

Choose installed dhcpcd version in Wheezy and Jessie
Jessie has different kernel for i386, fixing name for EC2.
Merge pull request #119 from rybaktomasz/unstable-kernel

Jessie has different kernel for i386, fixing name for EC2.
Merge pull request #117 from zeridon/fix-grub-options

Improvement in grub options for ec2
Convert "provider" into provider specific section
This is where all provider specific settings belong
like waagent on azure, guest additions iso path on vbox and virtualization type on ec2
Convert every JSON file to YAML
Lines removed: over 500. Readiblity gained: A shitload
Now you can actually get an overview of a manifest on a single screen height.
I am sure that it will also save a lot of hassle when modifying schema in the future.
No more "expected property name" etc. because of an extraneous comma
Comments are of course natively support, so there's no need for this minify_json hokey pokey
Take advantage of the YAML multiline notation
Factor release codename fetching out into common.tools
This allows code that runs before the bootstrapinformation object has been created
to also figure out the release codename
Do a basic validation of the manifest before accessing it.
This prevents cryptic error messages
Differentiate installation of grub 1.99 and grub 2
Clone packages-kernels.yml pattern to other providers
GCE also gets its own file.
For now, this scales - but we might want to refactor when there is more that just the kernel package we need to choose from
Refactor logging setup to be more modular
Allow passing data into the manifest.
This makes it possible to create dynamically created manifests
Update CHANGELOG
Add documentation for the run() function.
Also: Move the return statement in run() to the bottom