FreeText annotations rendering problems after reopening a document

[gtache]

The FreeText annotations are not displayed after saving them and opening the document again. It is possible to make them appear by moving the component or changing one of their properties.

[pcorless]

Added a combined PR of your changes and mine, that I think addresses the issue #202

[pcorless]

Marking as fixed, will create a new issue to address to a Page being garbage collected during an edit.