TST/CLN: pare down the eval test suite
Current running time of the `eval` test suite (not including `query`) 

```
$ nosetests pandas/computation/tests/test_eval.py                                                   1 ↵
......../home/phillip/Documents/code/py/pandas/pandas/core/frame.py:3088: FutureWarning: TimeSeries broadcasting along DataFrame index by default is deprecated. Please use DataFrame.<op> to explicitly broadcast arithmetic operations along the index
  FutureWarning)
.........................................................................................S.......................................................................................................................
----------------------------------------------------------------------
Ran 217 tests in 190.685s

OK (SKIP=1)
```

New running time :speedboat: :

```
$ nosetests pandas/computation/tests/test_eval.py
......../home/phillip/Documents/code/py/pandas/pandas/core/frame.py:3088: FutureWarning: TimeSeries broadcasting along DataFrame index by default is deprecated. Please use DataFrame.<op> to explicitly broadcast arithmetic operations along the index
  FutureWarning)
.........................................................................................S.......................................................................................................................
----------------------------------------------------------------------
Ran 217 tests in 39.299s

OK (SKIP=1)
```

can u include alignment tests at least on lhs for all index types
or does it make it take much longer?
 let me see
 okay doesn't add that much (about 3s) to do lhs all index types in the alignment tests (sans `PeriodIndex`)
 also unmarked a few `@slow` tests so that the basic alignment tests would run across all our builds except the slow which will run the more complicated tests
 gr8 I don't think we have the index interactions anywhere else so that's good
 @jreback merge?
 yep
