Remove jeweler from gemspec and remove version constraint from jeweler i...

`bundle update` is not working on a fresh checkout of the repo because of a version conflict between bundler and jeweler: 

```
~/workspace/oracle-enhanced $ bundle
Fetching gem metadata from http://rubygems.org/.......
Fetching gem metadata from http://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "bundler":
  In Gemfile:
    jeweler (~> 1.5.1) ruby depends on
      bundler (~> 1.0.0) ruby

  Current Bundler version:
    bundler (1.3.0)

This Gemfile requires a different version of Bundler.
Perhaps you need to update Bundler by running `gem install bundler`?
```
This commit gets bundle working again by removing the version constraint on jeweler from the Gemfile.  It also removes jeweler from the gemspec (it is unnecessary there).