Make context documentation more visible

[pierrecamilleri]

Hi, I could not find this feature nor a related request, I hope I did not miss any: I would like to specify that I am currently working on a specific project for some time, and that all my subsequent commands should be related to this project (except specifically overwritten).

For instance, if I specify "birthday_party" as current project, task should return output of task pro:birthday_party, task add should add to project "birthday_party" but task add pro:work should not. When I am done with birthday party planning, I should be able to return to normal behavior.

I see following benefits: less typing (less mental load) when adding several tasks to the same project, commands less prone to typing errors or omissions.