support for <palette sorted="true"> and <palette sorted="false"> in metamodel, which specifies whether to sort elements in a group and groups themselves by name or leave them in order specified by metamodel. Needed for TRIKStudio, where Smile and SadSmile blocks shall be adjacent. It also allows to fix some usability issues related to commonly used blocks are too hard to find in a palette.
2d model elements are now selected after they are added, it makes possible to edit their line thickness without selecting them
added "Minimize" and "Maximize" buttons for 2d model
Sensors moved from center of a robot forward a little, because they are barely visible on a robot
Zooming anchor moved to scene center
Merge pull request #1201 from qreal/sensors-moved-forward

Sensors moved from center of a robot forward a little, because they are ...
Merge pull request #1200 from qreal/2d-model-minimize-maximize

added "Minimize" and "Maximize" buttons for 2d model
Merge pull request #1199 from qreal/model-elements-selected

2d model elements are now selected after they are added, it makes possib...
Merge pull request #1198 from qreal/unsorted-groups

support for <palette sorted="true"> and <palette sorted="false"> in meta...
Increased sensor region for more convenient touch dragging;
Disabled 2D model reinitialization when active tab changes to non-diagram one
Merge pull request #1202 from dvvrd/touch

Zooming anchor moved to scene center
Merge pull request #1203 from dvvrd/robots

2D model fixes for geek picnic
Merge branch 'master' of https://github.com/qreal/qreal into sensors-synchronization

Conflicts:
	plugins/robots/robotsInterpreter/details/d2RobotModel/d2ModelWidget.cpp