Delete Gemfile.lock.

Per Yehuda Katz's advice[0], ditch the specific versions of gems specified
in the Gemfile.lock so that we are forced to get the dependencies
specified correctly in our Gemfile (or future gemspec).

[0]: http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/
Gemify!

Write a simple gemspec, move things into their appropriate directories,
and add a little Rake task to make it easier to generate a gem, install
it, publish it, etc.

Fixes #43.
Update installation instructions.

Also, fix incorrect ordering of example `ln` command.
Add clean to <TAB>-completions list
Fix pull, merge and start from non-TLDs

Pull #45 (f11ff4c) only fixed this for feature/hotfix switch. These
changes are needed any time git-submodule is run.

Also check for submodule updates in feature-merge.
Remove unneeded submodule init
Consolidate submodule functions and combine commands
Merge pull request #50 from iFixit/fix-hotfix-feature-from-anywhere

Fix pull, merge and start from non-TLDs
Merge pull request #51 from iFixit/add-clean-to-bash-completions

Add clean to <TAB>-completions list
Re-add readline import.

I mistakenly removed it in 84c9127 because I thought it had been
replaced entirely by highline in addd628; this is not true.

Readline is part of the standard library, so there's no need to include
it in the dependency list.
Merge gemify (#48) into master

Gemify!

Write a simple gemspec, move things into their appropriate directories,
and add a little Rake task to make it easier to generate a gem, install
it, publish it, etc.

Fixes #43.
Add gem version badge to README.

All the cool kids are doing it.
Submodule update: don't rebase

I think switching branches shouldn't rewrite my commits inside a
submodule.
Merge submodules-dont-rebase (#53) into master

Submodule update: don't rebase

I think switching branches shouldn't rewrite my commits inside a
submodule.
Hotfix: unify and improve hotfix branch name logic

Now you can specify the full branch name, or the branch name without the
'hotfix-' prefix.

Equivalent:
   hotfix switch hotfix-blah-blah
   hotfix switch blah-blah
hotfix_branch: some typos and bugs

thanks James!
Merge hotfix-branch-name-tolerance (#55) into master

Hotfix: unify and improve hotfix branch name logic

Now you can specify the full branch name, or the branch name without the
'hotfix-' prefix.

Equivalent:

    hotfix switch hotfix-blah-blah
    hotfix switch blah-blah
feature-cherry: Add feature cherry-pick
feature-cherry: Fix args require
feature-cherry: Actually use feature start