ERR: Fail-fast with incompatible skipfooter combos
Setup:

~~~python
from pandas import read_csv
from pandas.compat import StringIO

data = "a\n1\n2\n3\n4\n5"

# Case 1:
read_csv(StringIO(data), skipfooter=1, nrows=2)

# Case 2:
read_csv(StringIO(data), skipfooter=1, chunksize=2)
~~~

Currently, we get:

~~~python
# Case 1:
...
ValueError: skipfooter not supported for iteration

# Case 2:
...
<pandas.io.parsers.TextFileReader object at ...>
~~~

In Case 1, the error message is not correct.  True, passing in `nrows` and `skipfooter` is not supported (`skipfooter` should be skipping lines at the end of the file, **NOT** at the end of the `nrows` of data that we read in, which is what happens currently), but we should raise a better error message.

(BTW, the only way to make this combo work is that we read in the entire file before cutting off the last `skipfooter` rows but can look into that subsequently...)

In Case 2, creating this reader is deceiving.  Any attempt to call `.read()` on this will raise the `ValueError` seen in Case 1.  It is better that we alert end-users immediately that this reader doesn't work.  After this PR, we get some more useful error messages out of the gate:

~~~python
# Case 1:
...
ValueError: 'skipfooter' not supported with 'nrows'

# Case 2:
...
ValueError: 'skipfooter' not supported for iteration
~~~