Add DescriptionEntry to the activity sub-toolbar
Add DescriptionEntry to the activity sub-toolbar

This is the implementation of the 'Write to Journal anytime'
feature [1].

The patch itself adds a DescriptionItem to the activity
sub-toolbar to make editing a Journal entry description
from within the activity possible. The code has the same
error handling as the TitleEntry.

Signed-off-by: Simon Schampijer <simon@laptop.org>
Signed-off-by: Walter Bender <walter.bender@gmail.com>
Reviewed-by: Gonzalo Odiard <gonzalo@laptop.org>
Reviewed-by: Manuel Quiñones <manuq@laptop.org>

[1] http://wiki.sugarlabs.org/go/Features/Write_to_journal_anytime

quozl/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,ceibal-tatu/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,puneetgkaur/backup_sugar_sugartoolkit,tchx84/debian-pkg-sugar-toolkit-gtk3,puneetgkaur/sugar-toolkit-gtk3,manuq/sugar-toolkit-gtk3,puneetgkaur/sugar-toolkit-gtk3,puneetgkaur/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,puneetgkaur/backup_sugar_sugartoolkit,manuq/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,tchx84/debian-pkg-sugar-toolkit-gtk3,gusDuarte/sugar-toolkit-gtk3,gusDuarte/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,puneetgkaur/backup_sugar_sugartoolkit,gusDuarte/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,gusDuarte/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,ceibal-tatu/sugar-toolkit-gtk3,ceibal-tatu/sugar-toolkit-gtk3,tchx84/debian-pkg-sugar-toolkit-gtk3,manuq/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3