Add group_rows_by_project_and_version() to report_builder.py and replace
the duplicated inline grouping in both html.py and odt.py with a single
call to the shared function. This ensures consistent grouping behavior
across formatters and removes a maintenance burden — any change to
grouping logic now happens in one place.
Closes#19
get_version() now returns version.name instead of str(version), which
returned the numeric ID from redminelib.resources.Version. Falls back
to str() when .name is absent (#14).
Add issue.id as tertiary sort key in build_grouped_report so tasks
within the same project+version group always appear in the same order
regardless of API response ordering (#33).
Remove redundant sort from client.fetch_issues_with_spent_time — the
sort already runs in report_builder.build_grouped_report, so doing it
twice wastes CPU. Also remove the now-unused get_version import (#32).
Closes#14, closes#32, closes#33
