error when parsing values on win7 x64

Hi,
I have used both this pystdf and [stdfparser](code.google.com/p/stdfparser), and found both have wrong parsed results.

The original stdf file is generated on D10, with lines as below:

```
double manual_data[4];
manual_data[0] = 8000004;
manual_data[1] = 8000005;
manual_data[2] = 8000006;
manual_data[3] = 8000007;
csicVariableTest("manual_data","efuse_fail",manual_data,0,0xffffffff,"");
```
the std file is uploaded here: [stdf file](https://github.com/jinstrong/problems_files)

I have used the official parse tool, which gives correct result as below:

```
Dtr.rec_len = 65 MSB = 0x00, LSB = 0x41
Dtr.rec_typ = 50
Dtr.rec_sub = 30
Dtr.text_dat = test value is 8000006.000000 for testname manual_data at site 2
```
But with this tool, the result is parsed as 8000005.5, which is pretty strange. Please help take a look and fix this issue if time allows.