Support parsing thousands separators in floating point data
xref #584 

```
It seems that the decimal format works ok for the decimal sign or for the thousands but not combined.
Reopen the issue?

Example

import pandas as pd
from StringIO import StringIO
data = """A;B;C
0;0,11;0,11
1.000;1000,11;1.000,11
20.000;20000,22;20.000,22
300.000;300000,33;300.000,33
4.000.000;4000000,44;4.000.000,44
5.000.000.000;5000000000,55;5.000.000.000,55"""

df = pd.read_csv(StringIO(data), sep=';', thousands='.', decimal =',')
print df.dtypes
print df

Results in

A int64
B float64
C object
A B C
0 0 1.100000e-01 0,11
1 1000 1.000110e+03 1.000,11
2 20000 2.000022e+04 20.000,22
3 300000 3.000003e+05 300.000,33
4 4000000 4.000000e+06 4.000.000,44
5 5000000000 5.000000e+09 5.000.000.000,55
```
