added:
- interfaces
- SimpleCommandsFactory
- Cycle, which is meta-command

fixed:
- "compiler -> brainfuck virtual machine" dependency

removed:
- all tests from TestCompiler
added:
- interfaces
- SimpleCommandsFactory
- Cycle, which is meta-command
removed:
AddValueToCellCommand.java

added:
final attributes to some fields
removed:
Main.java

added tests:
testInterpreter
testCompiler
testLoopsOnCompiler

code refactoring
removed:
getMemorySize() in BrainfuckVirtualMachine
added:
testExecuter
Code reformatted
Optimized imports