Update benchmarks.

- Upgraded to new ActiveRecord API (table_name, limit, to_a).
- Locked to ActiveRecord >= 3.0. ^
- Used Mysql2::Error instead of undefined Mysql2::Mysql2Error.
- Specify root user to sequel benchmark. Other benchmarks are using password less
  root account.
- Fixed picking random array value in benchmark/setup_db.rb (1.8 and 1.9
  compat).

[ci skip]
Initialize read_timeout to avoid 'warning: instance variable @read_timeout not initialized'.
Merge pull request #399 from simi/benchmarks_update

Update benchmarks.
Merge pull request #400 from simi/avoid_warning

Initialize read_timeout
make sure write_timeout and local_infile ivars are setup to avoid warnings
get rid of some more warnings
clean up connections in specs where we can
some more spec cleanup
copy pasta err
went a little overzealous in my cleanup heh
Revert "make sure write_timeout and local_infile ivars are setup to avoid warnings"

This reverts commit e7e43411c5fd3191605b0dfb4d0dfb97c1466561.
Merge pull request #401 from simi/revert_warning

Revert "make sure write_timeout and local_infile ivars are setup to avoid warnings.
just skip these tests on rbx :\
If dir_config returns [nil, nil] this will prevent trying to index into nil
bump version for 0.3.13 release
Merge pull request #402 from sodabrew/libdir_again

Handle dir_config returning nil, nil on Windows.