Centralize deployment target

- Set the deployment target at the project level instead of at the
  target level. This mimics the behavior of Xcode.
- Configure the deployment target with ProjectConfiguration.
- Use the deployment target information to populate values inside
  templates.
Be more specific about not linking Info.plist file

Previously, we were filtering out all plists from being linked against
the target. However, in actuality, we should allow users to link
template plists, and only prevent the linking of Info.plist files.
Reluctantly allow the use of tabs for indentation

Everyone knows that you _should_ be using spaces for indentation and not
tabs, but some people insist on being wrong, so we shouldn't make it
hard for them to be wrong.

This adds a `use_tabs` key to the configuration. By default, this key is
false, the way God intended, but people that feel like being insane can
change it to configure their project to use tabs instead of spaces.

Note that this _doesn't_ affect the templates. It's recommended that if
you want to use tabs everywhere, you override the templates to match.
Add configuration for setting up Run Script phases

This adds the ability for users to define custom Run Script build phases
to be added to the main application target. By default, we're only
adding the original TODO/FIXME comment script

- Adds `run_script_phases` key to configuration. The value for this key
  is an array of dictionaries. The key for the dictionary will be used
  as the filename of the template script and the value will be used as the
  name for the script inside Xcode.
- Removes the `install_todo_script` key from the configuration. This key
  is superseded by the `run_script_phases` key.

Fixes #118
Update liftoffrc(5) for script phase changes
Add basic travis config
Remove Travis config for now

Because of the issues building the native C extension for Xcodeproj,
Travis isn't able to get past bundle install. I'll come back to this
later.
Add deprecation manager

This class will handle the mappings between deprecated keys and their
replacements.
Break configuration attributes into multiple lines
Merge branch 'master' into jp-strict-prompts

* master:
  Break configuration attributes into multiple lines
  Add deprecation manager
  Remove Travis config for now
  Add basic travis config
  Update liftoffrc(5) for script phase changes
  Add configuration for setting up Run Script phases
  Reluctantly allow the use of tabs for indentation
  Be more specific about not linking Info.plist file
  Centralize deployment target

Conflicts:
	lib/liftoff/project_configuration.rb