Fix spec bustage

I really don't run these specs often enough, do I?

Borked since 30befefba80f.
Add .ruby-version file

This is just for convenience in the local development environment.
Add Vroom as a submodule

Going to explore using this for testing purposes.

Added with:

  git submodule add https://github.com/google/vroom.git vendor/vroom
  cd vendor/vroom
  python setup.py build && sudo python setup.py install
  cd -

See:

  https://wincent.com/issues/2160
doc: Note 1.9 in the list of performance-related releases
Update docs for 1.10 release
Update authorship information

May as well do some Internet dealiasification.
Remove donation info from docs

I've received about 200 euros in donations over the course of 4 years,
which is a few cents per day. May as well reduce clutter in the docs by
dropping the references to it.
Abbreviate license headers

There are plenty of diverse opinions on whether it's worth it to include
full license text in every file:

- http://lu.is/blog/2012/03/17/on-the-importance-of-per-file-license-information/
- http://softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html
- http://stackoverflow.com/questions/845895/putting-license-in-each-code-file

The main argument against is verbosity. The main argument for is
ensuring that licensing info stays with the file even if it gets pulled
out of a project.

Seems that for a project like this one, the cost of license abuse is
low, and people's awareness of what the "BSD 2-clause license" is is
relatively good, so a terse point to the BSD license should suffice.
Don't depend on bundler in Rake tasks

This was crashing for me via Bundler, probably due to some
Nokogiri/libxml craziness. Just `gem install mechanize` and run normally
instead.