read_sql_table bug on columns with dots
read_sql_table handles columns with dots in the name incorrectly (removes name before dot)

```
from sqlalchemy import create_engine
import pandas as pd
engine = create_engine('sqlite://')
conn = engine.connect()
conn.execute("create table test (a int, `b.c` int)")
conn.execute("insert into test values (1,2)")
df = pd.read_sql_table("test", engine)
print(df)
```

->

```
    a  c
0  1  2
```
