Contract factories and bytecode introspection (#305)

* Support for CREATE, CLONE and BYTECODE_HASH

* Add missing files

* Pushed the clone example through the typechecker

* CLONE compiles

* Fix dependent type in CLONE

* Bytecode hash fixes

* Refactor

* Refactor 2

* move some logic away

* Fixed some error messages. Type inference of child contract still does some random shit\n(mistakes arguments with result type)

* CREATE sometimes compiles and sometimes not

* Fix some scoping/constraint issues

* works, needs cleanup

* cleanup

* Fix some tests. Remove optimization of singleton tuples

* Fix default argument for clone

* Cleanup

* CHANGELOG

* Mention void type

* Address review, fix some dialyzer errors

* Please dialyzer

* Fix failing tests

* Write negative tests

* Docs

* TOC

* missing 'the'

* missing 'the'

* missing 'the'

* missing 'the'

* mention pre-fund

* format

* pre-fund clarification

* format

* Grammar in docs

test/contracts/create.aes

@@ -0,0 +1,28 @@
+contract IntegerAdder =
+  entrypoint init() = ()
+  entrypoint addIntegers(x, y) = x + y
+
+contract IntegerAdderHolder =
+  type state = IntegerAdder
+  stateful entrypoint init() = Chain.create() : IntegerAdder
+  entrypoint get() = state
+
+contract IntegerAdderFactory =
+  entrypoint init() = ()
+  stateful entrypoint new() =
+    let i = Chain.create() : IntegerAdderHolder
+    i.get()
+
+payable contract ValueAdder =
+  entrypoint init() = ()
+  stateful entrypoint addValue(x) =
+    let integerAdderFactory = Chain.create()
+    let adder = integerAdderFactory.new()
+    adder.addIntegers(x, Contract.balance)
+
+main contract EnterpriseContract =
+  entrypoint init() = ()
+  stateful payable entrypoint increaseByThree(x) =
+    require(Call.value >= 3, "Price for addition = 3AEtto, insufficient funds")
+    let threeAdder = Chain.create(value = 3)
+    threeAdder.addValue(x)