title: matplotlib text boxes automatic position
body: <p>I would like to position a text box with keyword arguments like those used with legend 'loc' option, i.e. 'upper left', 'upper right', 'lower right', 'lower left'.
  The basic purpose is to align the text box with legend.
  I found a suggestion here : <a href="https://stackoverflow.com/questions/7045729/automatically-position-text-box-in-matplotlib">automatically position text box in matplotlib</a> but it still uses coordinates with which I have to play to get what I want, especially if I want to put it on the right of the plot area depending on the length of the text put in the box. Unless I can set one of the right corner of the text box as the reference for coordinates.</p>