Merge remote-tracking branch 'origin/titleItems'
updated changelog, changed version to 0.3.1
Fixed segfault when reshaping edge through the label
UML Class Diagram
creating children from parents context menu
added enums
links reconnect to children fixed
properties
fixed creating too much elements from menu
whitespaces and translation
class diagram rename
access type enum; showing access type for fields
Merge branch 'master' of https://github.com/qreal/qreal into class_diagram

Conflicts:
	qrgui/umllib/element.h
Merge branch 'master' of github.com:qreal/qreal into robots

Conflicts:
	qrgui/umllib/label.cpp
Fixed segfault when removing explosion source and target sequentially;
Fixed segfault when undoing global action;
== Id() replaced with .isNull() // TODO: replace != Id()
Merge branch 'master' of https://github.com/qreal/qreal into class_diagram

Conflicts:
	qrxc/graphicType.cpp
Merge branch 'master' of https://github.com/qreal/qreal
Merge branch 'bp-0.3.1'
added linkers for class diagram; bpmn is commented in plugins.pro
Merge branch 'master' of github.com:qreal/qreal into robots