PERF: enhance HDFStore Table writing performance
Took out all of the cython code, turns out you can assign directly to numpy recarrays per
column if you put in the correct shape yourself 

```
Invoked with :
--ncalls: 5
--repeats: 5
-------------------------------------------------------------------------------
Test name                                    | head[ms] | base[ms] |  ratio   |
-------------------------------------------------------------------------------
write_store_table_mixed                      |  45.6208 | 121.5352 |   0.3754 |
write_store_table_panel                      |  59.4140 |  99.5456 |   0.5969 |
write_store_table                            |  40.2264 |  65.8978 |   0.6104 |
write_store_table_dc                         | 143.3910 | 174.9424 |   0.8196 |
read_store_table_wide                        |  16.8930 |  17.5310 |   0.9636 |
query_store_table_wide                       |   9.6692 |   9.7564 |   0.9911 |
write_store_table_wide                       | 117.8906 | 118.8232 |   0.9922 |
read_store_table_mixed                       |   4.7604 |   4.7478 |   1.0026 |
query_store_table                            |   4.2646 |   4.2320 |   1.0077 |
read_store_table                             |   2.3678 |   2.3178 |   1.0216 |
read_store_table_panel                       |  20.9388 |  20.3526 |   1.0288 |
-------------------------------------------------------------------------------
Test name                                    | head[ms] | base[ms] |  ratio   |
-------------------------------------------------------------------------------

Ratio < 1.0 means the target commit is faster then the baseline.
Seed used: 1234

Target [d11041d] : PERF: enhance HDFStore Table writing performance
Base   [aca1a42] : Merge pull request #4437 from cpcloud/fix-astype-calls

```

Jeff this looks fantastic for writing tables. Does this enhancement also apply when appending to an existing table?

I cant wait to give this a shot once 0.13 is out. :+1: 
 http://pandas.pydata.org/pandas-build/dev/

there are are binaries out (iirc you use windows)

this works for appending / writing (it's the same operation )
