[ocrfeeder] (15 commits) ...Fix error when deleting a page

[Joaquim Manuel Pereira Rocha <jrocha src gnome org>]

Summary of changes:

  c0366bd... Prevent errors when the OCR engine's configuration has unkn (*)
  936d06e... Fix saving a previously loaded and edited project (*)
  92bedca... Add language capabilities to the Engine class (*)
  55f844d... Pass the new language's configuration to the OCR Engine's i (*)
  1f20671... Add the new language configuration to the DataBox class (*)
  c7ac930... Add languages capabilities to the BoxEditor (*)
  aba0e87... Add the language settings to ConfigurationManager (*)
  dacc9db... Assign the configured language before performing the recogn (*)
  113f5d3... Make engine class ignore $LANG argument if no favorite lang (*)
  06c20e4... Clean languages combo's code (*)
  ebaddbc... Add default language settings to PreferencesDialog (*)
  a7636ee... Add new language settings to the OcrEnginesManager and OcrS (*)
  4422b94... Fix problem when adding new OCR engine from SettingsManager (*)
  f071e95... Update Tesseract and Cuneiform's default arguments (*)
  c084be5... Fix error when deleting a page (*)

(*) This commit already existed in another branch; no separate mail sent