Print plugin fit to bounding box option

When you activate this option, the print preview is fixed to the actual bounding box and hides the scale.

This commit adds neccesary changes to:

* PrintProvider.js
* PrintPage.js
* PrintMapPanel.js
* PrintPreview.js
* Print.js

Yo can activate this option in Print plugin with  `"bboxFit": true` in mapStoreConfig.js.

This pull request fixes #241