initial work on UIComponent class
example of usage UIComponent instance with required changes in UIFactory, compontens and SpecialStyleguide
Revert "example of usage UIComponent instance with required changes in UIFactory, compontens and SpecialStyleguide"

This reverts commit 7658ec1f6d5db7df878e54e73750d46dd7c6f049.
DAR-810 Added local caching for Template Engine

Typo fixes
Added missing self:: for class constant
Added local cache for template engine to avoid multiple instantiations
if the component is rendered more than once.
manually merged styleguide branch into DAR-810
DAR-810 Moved exceptions from general ones to UI-specific
DAR-810 Added validation of required params
changed the way of getting exception message
added doc blocks
renamed two methods so the names are more descriptive
fixed linting issues
first unit test for UIComponent; small changes in the class to make unit testing possible
small change in setTemplate() and more unit test cases for it
DAR-811: Prepare templating & css for button component
WIP: get started button first try of rendering with UIFactory/UIComponent
DAR-810 | DAR-811 | added new methods to UIFactory and UIComponent to set base template path
integrated UIFactory and UIComponent and rendered "Get Started" button on Sepcial:Styleguide page
moved shared logic to static method for now
fixed unit test after changes in UIComponent
added new constant for memc