Log Message:
Update ruby-rspec-core to 2.10.1.

### 2.10.1 / 2012-05-19
[full changelog](http://github.com/rspec/rspec-core/compare/v2.10.0...v2.10.1)

Bug fixes

* `RSpec.reset` properly reinits configuration and world
* Call `to_s` before `split` on exception messages that might not always be
  Strings (slyphon)

### 2.10.0 / 2012-05-03
[full changelog](http://github.com/rspec/rspec-core/compare/v2.9.0...v2.10.0)

Enhancements

* Add `prepend_before` and `append_after` hooks (preethiramdev)
    * intended for extension libs
    * restores rspec-1 behavior
* Reporting of profiled examples (moro)
    * Report the total amount of time taken for the top slowest examples.
    * Report what percentage the slowest examples took from the total runtime.

Bug fixes

* Properly parse `SPEC_OPTS` options.
* `example.description` returns the location of the example if there is no
  explicit description or matcher-generated description.
* RDoc fixes (Grzegorz Świrski)
* Do not modify example ancestry when dumping errors (Michael Grosser)