Revert "Don't allow selection of parents items."

This reverts commit b4037eff2cf52b5cd13e1f1ea2088c543bdf09d1.
Allow tracking tasks to parents.
Enforcing tracking to leaf tasks only via the charm UI doesn't seem to be a good solution to problem, and is also not a good solution for a generic time tracking tool.
Merge pull request #81 from dfaure-kdab/master

Fix truncated items in the week combo (timesheet dialog)
Merge pull request #82 from dfaure-kdab/master

Fix combo width in the activity dialog too, for Andras.
Add "trackable" property to tasks.
Set by default, unsetting it prevents time to be tracked to the task.
This requires a database upgrade (which is performed automatically)
Merge pull request #80 from frankosterfeld/allow_track_to_parent

Allow track to parent
Update DeployQt4 to CMake 2.8.8 version.
Implemented Undo support in EventView
Fix CMake logic.
Merge pull request #83 from NicholasVanSickle/undo2

Implemented Undo support in EventView
Update Qocoa version with various fixes.
For display, use as short as possible but unique task names.
In the UI, don't use full paths but only prepend parent names until the resulting name is unique. (with at least on parent)

E.g.

/Projects/Foo/Development
/Projects/Bar/Development
/Unproductive/Vacation

becomes:

Foo/Development (Development is not unique, so prepend their parents)
Bar/Development
/Unproductive/Vacation (unique, but we prepend at least one parent)
Merge pull request #87 from frankosterfeld/smart_task_names

For display, use as short as possible but unique task names.
Update about screen
Do not accidentally edit the end time.
When moving the end date before the start date while editing, the changed signal of the duration edits triggered the end time to be set to the start time.
Increase maximum value of the duration/hours spinbox.
This ensure that its value is always in sync with the start and end datetimes while editing.
Add experimental KWallet support.
Update to latest QKeychain version with experimental KWallet support.
This is used the new asynchronous QKeychain API.
Update to qtkeychain@be7f9c6d
Merge pull request #88 from frankosterfeld/async_keyring

async qtkeychain, kwallet support
Set focus on filter line edit in SelectTaskDialog