Converted JetDeclarationJoinLinesHandler to Kotlin
Moved some code from DeclarationUtils to JetDeclarationJoinLinesHandler and refactored it
Fixed bug in join lines
Better way of changing property intiailizer used
Moved test data
Moved code from DeclarationUtils and refactored code
Moved and renamed class + added check for JetFile
KT-4849 'Join lines' should remove braces from single-statement block

 #KT-4849 Fixed