Make all classes of DSL from one package to simplify imports
System properties
Support isSet() on properties
Target dependencies
Remove isSet() from Property. Property with default value is also considered as set. In our DSL it becomes set after the first access.
.equals -> == for strings
Respect *.properties
Support code generation for external libraries
Support nested types
Merge branch 'master' into example

Conflicts:
	dsl/src/ru/ifmo/rain/mekhanikov/antdsl/Base.kt
	dsl/src/ru/ifmo/rain/mekhanikov/antdsl/Properties.kt
	src/ru/ifmo/rain/mekhanikov/ant2kotlin/DSLGenerator.kt
	test/Ant2KotlinTestCase.kt
	test/DSLGeneratorTest.kt
	testData/DSLGenerator/TarUntarTest.kt
UpdateProperties works now