Redefined manager flags so that the flags related to notebooks style are in the lower 16 bits. This way they can be used verbatim as the wxAuiNotebook window style flags.
Make sure that the manager of a wxAuiNotebook has it's flags set from the wxAuiNotebook specific class style flags (aka the lower 16 bits of the window style flags). This fix the unexpected appearance of the closing box in wxAuiNotebook.
Ensure that a pane in a wxAuiNotebook is always in a tab, even if it's alone
Fixed invalid test leading to think any pane belong to any notebook part on some circonstances
Fixed incorrect feedback when splitting in wxAuiNotebook