Checkstyle coding-style rules

-avoid using tabs
-avoid trailing whitespaces
-no windows eol chars
-indentation offset 4
-imports order - static imports first, alphabetical order
-avoid unused imports

Change-Id: I4ea8193089f7c5cf77ee432c85cb1c8249043495
Signed-off-by: Milos Fabian <milfabia@cisco.com>
Merge "Checkstyle coding-style rules"