BUG: Fix smaple_names being casted to int/float

read_csv was casting the `'sample_name'` column to a float if the values
were of the form `0000012.122204`, this has been fixed and we have also
added a new keyword argument to skip lines that are "empty" or that lack
a sample_name i. e. if a line starts with a `\t` character it will be
ignored. Empty columns are also now removed.
STY: Fix FLAKE8 errors 👎
TST: Add test for sample_names that are numbers
Merge pull request #643 from ElDeveloper/comments

BUG: Fix smaple_names being casted to int/float