read_csv() - "skiprows" should ignore "comment"
#### Code Sample, a copy-pastable example if possible

```python
pandas.read_csv(URL, delimiter='|', comment='#', skiprows=4)
```
#### Problem description

`ParserError` when reading CSV files with comments at the beginning of the file. Line count of comments varies.

EDIT: `ParseError` is due to the fact that the column count of the first 4 rows is different from the column count of the succeeding rows

Objective:
- Ignore comments
- Ignore the first 4 lines that are not comments

This happens when reading a CSV file similar to the following
```
# Comment start
# ..... Comment count varies
# Comment end
first|line
second|line
third|line
fourth|line
first|data|to|read
second|data|to|read
```

#### Expected Output

The comment lines should not be included on the skiprows

#### Output of ``pd.show_versions()``

<details>
[paste the output of ``pd.show_versions()`` here below this line]
commit: None
python: 3.6.6.final.0
python-bits: 32
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 142 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
pandas: 0.23.4
pytest: None
pip: 18.1
setuptools: 40.4.3
Cython: None
numpy: 1.15.2
scipy: None
pyarrow: None
xarray: None
IPython: None
sphinx: None
patsy: None
dateutil: 2.7.3
pytz: 2018.5
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: None
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
</details>
