Issue title: Included css files overrides bootstrap css ?
 Issue body: Hello,
I`m kinda new to react so sorry if i sound so 'noob' . I`m using some buttons from material-ui with tooltips in a row. The problem is that after i include the css for table , the tooltips from the icon buttons hide under the next row

Is there a way to solve this problem?

Thanks
 Comments: 
 Comment 0: @Rus-Cosmin, sorry for lately reply, I'm not very familiar with material-ui so could please show me the different part for before and after adding the css of ```react-bootstrap-table```, I thought it's easy that you can check on the chrome with opening inspect.

Let me know if you still have any questions
{'source': 'GithubIssues', 'repo_name_with_owner': 'AllenFang/react-bootstrap-table', 'issue_id': 200478348, 'repo_stars': 2477.0}