ImageBox's image will reload when error happens.
Bug fix in render_formula.
Change BasicEntity to BasicComponent.
Replace ImageBox class with MultiRowComponent and LatexCodeImage class.
Fix 'constuctor' to 'constructor' in SelectRow and SelectRowOrColumn.
Adjust radius of TargetGate and Control.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	app/assets/javascripts/qcircuit_editing/helper.js.coffee
Merge remote-tracking branch 'upstream/master'

Conflicts:
	app/assets/javascripts/qcircuit_editing/helper.js.coffee

Bug with MeasureTab