[diagrams] Usability improvements
 * Choose default attribute value for interpolation if none is set
 * Remember last used tab
 * Default for scale dependent visibility matches layer settings
[diagrams] Show message on messagebar instead of messagebox
And some indentation updates
more spelling fixes
catch system signals and stack trace on linux
html identify results: catch loadFinished only once
[sextante] added back script creation tools to toolbox
[sextante] fixed help edition dialog.
[sextante] edited description of OTB orthorectification algorithm
[pyqgis-console] some fix for find text in editor
- changes tabs to north
[pyqgis-console] minor fixes and cleanup
[pyqgis-console] fixes translation strings
update french translation
replace old select calls with getFeatures method
write field names in the same encoding as attribute values (fix #4540)
[sextante] model outputs are now shown in canvas
Merge pull request #578 from minorua/fieldname_encoding

write field names in the same encoding as attribute values (fix #4540)
[sextante] fixed problem when defining help files for the first time
Merge pull request #575 from Jean-Roc/mywork

update french translation
[pyqgis-console] add a context menu for tabs
[pyqgis-console] fix typo and indentation update