Initial version based on work done on some prototypes.
There is the basic behavior :
- one tab for each function : translate, defintion
- the context is shared between tabs (serched text, lang...)
- the connexion on the glosbe server is ok
forgot some files in git (flags)
rename of file TranslateTab.qml
more refactoring of event code
still refactoring js code for events

added optimisation to not ask suggestions on some events
handling of suggestions in general context
added preliminary support for lang selector in definitionTab
internal API change for update of context
creation of an independant LangSelector popover
initial version of langSelector for translation tab
correction when switching langs
Handling of default focus : always on seearch textfield
cleaning code of unused toolbar items