Revisions and initial impl of installkit conditional dependencies.

## Ready State: Yes

* Added Drupal core patch for the `system_list` function, allowing profiles to be loaded during the installation even though they may not have been "installed" yet. This allows for hooks to be implemented and executed within the profile itself (for example: `hook_system_info_alter()`).
* Bugfix for `$install_state` that is passed by reference (known as `context`) to the installation task objects themselves.
* Implementation of `imagex_installkit[dependencies][conditional][]` `.info` option for modules.
* Removed the implementation of hook `hook_imagex_installkit_install_profile_modules_alter()` in favour of the `hook_system_info_alter()`.
* Moved `theme_disable(array('bartik'))` only if a default theme has been specified by a derived profile.
* Codebase cleanup to adhere better to Drupal coding standards.
* Removed unneeded themes from the `drupal-org.make` in favour of ImageX's BuildKit.
* Removed the "block" helpers for installation and setup of blocks.

## Deployment

* Merge code.