Bundler is no longer a runtime dependency.

Deployment tools like RVM and Passenger anyway activate Gemfile. It doesn't
have to be done from within the application.

Side effect?

While the executable will work perfectly when SequuenceServer is installed as a
RubyGem, running bin/sequenceserver from the repository can fail:

1. If 'sequenceserver' gem is installed, the executable will load the installed
    gem if RubyGems is loaded instead of loading SequenceServer from the
    repository.
2. If 'sequenceserver' gem isn't installed or RubyGems isn't loaded, the
    executable will fail with a stack trace.

To avoid either just `bundle exec bin/sequenceserver` during development or
when trying to use SequenceServer from git.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Remove jeweler.

Thus reversing the role of gemspec and Gemfile. So we can run bundle exec
bin/sequenceserver during development again (crucial to this functionality
is calling `gemspec` in Gemfile).

Gone with jeweler are unnecessary dependencies some of which still work on Ruby
1.8.7 and some that don't (yes, we need to support 1.8.7 as long as it takes).

Other changes:
1. In the gemspec, added myself back to `spec.email`.
2. Removed `rake rdoc`. Do we need it?

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
On Travis, test on Ruby 2.1.1 and 2.1.2 as well.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>