[skip ci] Latvian translation and Russian i18n guide 

Update app templates to use bootstrap ActiveForm

[skip ci] Update README.md  instruction for install core framework.

Updated instructions for the current reality.

[skip ci] jquery .val() not .value

[skip ci] Update tutorial-template-engines.md

just fixed typo

In line 180. 
It should be .val() instead of .value.

This is my first edit.

[skip ci] Create start-hello.md

close #5214

tests are not allowed to fail anymore.