Column headers from CSV are different when using read_csv vs DataFrame.from_csv
Steps to reproduce,
- Create a string representation of a CSV file
- Convert it into a StringIO object
- Read it using pandas.read_csv
- Read it using pandas.DataFrame.from_csv
- The parsed headers will be different

```
# Testcase
import pandas
import cStringIO as StringIO

data = """col1|col2\ndata1|data2\ndata3|data4"""
file1 = StringIO.StringIO(data)
file2 = StringIO.StringIO(data)
r = pandas.read_csv(file1, delimiter="|")
r_  = pandas.DataFrame.from_csv(file2, sep="|")


print "Version: ", pandas.version.version

print " -- Data --"
print data

print "-- Headers --"
print r.columns.values
print r_.columns.values
```

```
# Output
Version:  0.16.0
 -- Data --
col1|col2
data1|data2
data3|data4
-- Headers --
['col1' 'col2']
['col2']
```
