[REF] hr_recruitment: removed base_stage inheritance, state field. Updated views / reports. Still not updated subtypes.
[FIX] hr_recruitment: removed get_default_email that was in most cases unnecessary
[MERGE] Sync with trunk
[IMP] hr_recruitment: button 'create employee' now a link next to the emp_id field.
[MERGE] Sync with trunk
[MERGE] Sync with trunk
[FIX] Removed get_default_email, already removed but that came back when merging trunk
[IMP] hr_recruitment: added date_last_stage_update field, holding date of last stage modification; removed hired.employee wizard that does not seem to be used anywhere, nor to be useful.
[MERGE] Sync with trunk
[IMP] hr_recruitment: added date_last_stage_update and stage_id in search
[FIX] hr_recruitment: fixed onchange_department causing the stage to be resetted
[DOC] hr_recruitment: added doc directory + changelog + first draft of doc about stage / state
[ADD] hr_recruitment: added forgottent doc file
[MERGE] Sync with trunk
[DOC] hr_recruitment: added some documentation
[DOC] Added a forgotten line.
[DOC] Added forgotten change on changelog.
[REF] hr_recruitment stage management cleaning

Using stages and states is not easy to manage. Indeed those two fields mess with the same basic concept. This task remove the state on hr.applicant model, leaving only stages.

Main features:
- removed base_stage inheritance on hr.applicant model
- removed state field on hr.applicant model
- removed state field on hr.recruitment.stage model
- removed date field on hr.applicant model, not used anywhere; other date fields are considered as sufficient
- added date_last_stage_update on hr.applicant model, holding the date of the last stage change, allowing reporting and analysis on time spend in stages
- date_open is set when assigning an user to the applicant; date_open now means assignation date

This allows to remove nearly all buttons on the form view. As the statusbar is clickable, the only remaining action is to create an employee from the applicant, which is a link button in the form view.

Subtypes have been updated :
- new applicant: stage_id.sequence=1
- other: stage change

Misc:
- [IMP] views accordingly;
- [IMP] reports accordingly, added date_last_stage_update in reports;
- [IMP] subtypes: New, Stage Changed and Hired are kept;
- [REM] removed some tests because they are not applicable anymore;
- [DOC] doc directory + changelog + stage explanation;
- [REM] removed hired.employee wizard