Disable dock widget text eliding

[VictorLamoine]

Fixes #1148

Diff without trailing whitespace changes:
https://github.com/ros-visualization/rviz/compare/kinetic-devel...VictorLamoine:QTabWidget_elide?w=1

The new slot onDockPanelChange checks for every QTabBar there is in the main window and makes sure text is not elided inside it.

This slot is triggered

• When a config file is loaded
• When a panel is created
• When a panel is moved

Before

After

[VictorLamoine]

Rebased against current kinetic-devel.

[dhood]

This looks good thank you @VictorLamoine !

[dhood]

for future reference I tested with this config:
test_tab_eliding.rviz.txt

[theobslhc]

I think this PR introduces a Qt5 dependency, but branch kinetic-devel is supposed to be Qt4-compatible. (Edit: it's not)

src/rviz/visualization_frame.cpp, line 1208

QList<QTabBar *> tab_bars = findChildren<QTabBar *>(QString(), Qt::FindDirectChildrenOnly);

The Qt::FindDirectChildrenOnly flag was introduced in Qt5.

Everything seems to build fine with Qt4 and without the commits.
Is there any solution that would not rely on Qt:FindDirectChildrenOnly flag? (I might try to look into that myself soon - will update)

[rhaschke]

@theobslhc, thanks for reporting this issue. Please file a new issue for this, referring to this PR.
@VictorLamoine Do you have an idea to handle this issue?

[theobslhc]

See issue #1369.