Enable user to go back into the process while adding a book

[Zelig880]

At the moment, an user is not able to go back while adding a book, and is forces to refresh the page to be able to add a new book (for example if they clicked on teh wrong title).

• Add a button on the bottom right of as shown in the attached picture if the add to your bookshelf is shown
• SHow the button only if a title has been selected from the dropdow
• Name the button "Start again" and use secondary theme
• When the button is clicked, cleanup the selected book variable and make sure the form is reset to its initial state
  

[venkivijay]

@Zelig880 I have raised PR #59 for this issue. Please review it.

I used refs to access searchText and clear it as the Button triggering the reset and BookshelfAddStep1 components are Siblings.