minimize dock-widgets in a statusbar

User has option of minimizing dock widgets. Also he can
enter fullscreen mode by going to the View menu or by
pressing F11. When exiting fullscreen mode the state will
be the one before the fullscreen. If some widgets were
hidden before they will remain that way after.

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
Fix styling issues and tiny bug

- fix styling issues for the minimizing widgets code
- force fullscreen when some widgets have been manually brought
on screen (opposite of manual minimization).
Merge pull request #391 from marius-avram/B331-NEW

minimize dock-widgets in a statusbar
fixed compilation on Windows.
Improved fixes for issue 259 with new icon for clear frame button
Moved MinimizeButton to separate file

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
Fix SEGFAULT when watch_file_changes is false

I haven't seen any bug with this, but at least on my machine
I can't open any project file when watch_file_changes is false,
because i get a SEGFAULT. This fixes the issue.
Merge pull request #395 from marius-avram/watch-file-segfault

Fix SEGFAULT when watch_file_changes is false
Hided scroll bars on RGBA-label QTextEdit-widget.
Related to issue https://github.com/appleseedhq/appleseed/issues/364
Merge pull request #394 from marius-avram/B331-refactor

Moved MinimizeButton to separate file
Merge pull request #396 from liiza/bugfixing

Hide scrollbars on RGBA QTextEdit widget.
small code tweak.
minor cosmetic fixes for issue 259
minor code tweaks.
Merge pull request #393 from sriravic/issue259imp

Improved fixes for issue 259 with new icon for clear frame button
Merge remote-tracking branch 'upstream/master'