Use "Space" key to start and stop a timer

[tanius]

Not too sure about this, but: since the Space bar key is not needed right now in the project tree and timeframes list, it could be a convenient keybinding for both starting and stopping the timers. Especially in combination with the current style of navigating the project tree using up and down arrows (for moving up / down) and left and right arrows (for folding / unfolding an entry).

So:

• When a project with an active timer is selected, Space would stop that timer.
• When a project without an active timer is selected, Space would stop any active timer or another project (if any) and then start a timer for the selected project. Which is what "Project → Start timer" does right now.

[jansorg]

I'd like to keep the feature that "Start timer" on a project with the active timer stops the current and then creates a new entry. This might be useful to start a new task on the same project.

The next update has :

• space to start a new timer on the currently selected project
• shift + space to stop the currently active timer