title: pandas read_html() ignore superscripts and subscripts
body: <p>I am trying to make dataframes from sites like:
  <a href="https://www.ncbi.nlm.nih.gov/books/NBK56068/table/summarytables.t4/?report=objectonly" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/books/NBK56068/table/summarytables.t4/?report=objectonly</a></p>
  <p>If you look at the column headers for Water, there is a superscript 'a' that is a hyperlink and 'b' for Protein so my dataframe column headers end up as 'Watera' and 'Proteinb'.</p>
  <p>I could go through and edit them one by one but is there any way programatically to ignore subscripts and superscripts or hyperlinks?</p>