Addss template clearing when in debugmode

(cherry picked from commit 7d2f6c13c36726868d0f4ad478a7ccf72d793c3a)
adds getByQuery to entityService

(cherry picked from commit 825861905555633f7a778d9c90274c811439abea)

Conflicts:
	src/Umbraco.Web.UI.Client/src/common/resources/entity.resource.js
	src/Umbraco.Web/Editors/EntityController.cs
Adds support for xpath root node selection on mntp

(cherry picked from commit d842f0f5b7fe4322915eab0e4b12f73cdf95e115)

Conflicts:
	src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js
fixes mntp filtering

(cherry picked from commit 3e22598f4a0ec4be50082d5d5d5fc79dd15d8be7)
Fixes inconsistently named private method

Replaces delegates with lambdas

(cherry picked from commit 2a811627565769ad43c9854d36be51edc04c6873)
Final tweaks to TreeSource picker

Better help text, polish icons and margins, made sure it toggles UI
correctly for each type of tree

(cherry picked from commit 9ce79e98a3dc8427503dd33f3f4ffc101ad48366)

Conflicts:
	src/Umbraco.Web.UI.Client/src/views/prevalueeditors/treesource.html
Missing changes on ContentPickerControler re-added