Fix translation for fiscal period filter.
Add by_employee filter.
Patch update of rake gem.
Update bookyt_salary to new minor version.

Changes include:
* Use boot_nav_filter for salary statistics filter.
* Do not use striping for salary item list form.
* Better titles for statistics columns.
* Fix title for salary statistics.
* Use by_calendar_year filter in ahv statement.
* Add year filter for salary declaration report.
* translations in navigation for all reports.
* Use year filter for salary statistics report.
* Show detailed statistics for each month.
* Add employee filter to statistics.
* Add common employee filter to salary declarations.