Move Cash into new contracts subfolder, move base code into core

src/contracts/Cash.kt

@@ -1,3 +1,4 @@
+import core.*
 import java.security.PublicKey
 
 /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

src/core/ContractsDSL.kt

@@ -1,3 +1,5 @@
+package core
+
 import java.math.BigDecimal
 import java.util.*
 import kotlin.math.div

src/core/Crypto.kt

@@ -1,7 +1,8 @@
+package core
+
 import com.google.common.io.BaseEncoding
 import java.security.MessageDigest
 import java.security.PublicKey
-import java.util.*
 
 // "sealed" here means there can't be any subclasses other than the ones defined here.
 sealed class SecureHash(bits: ByteArray) : OpaqueBytes(bits) {

src/core/Main.kt

@@ -1,3 +1,5 @@
+package core
+
 // TODO: Make a decision on basic timestamping approach (use external TSAs? use fake TSA?)
 // TODO: Think about how to expose time to the contract
 // TODO: Pick a serialisation solution for the prototype (kryo?)

src/core/Structures.kt

@@ -1,3 +1,5 @@
+package core
+
 import java.security.PublicKey
 import java.security.Timestamp
 

src/core/TestUtils.kt

@@ -1,3 +1,5 @@
+package core
+
 import java.math.BigInteger
 import java.security.PublicKey
 import kotlin.test.fail

src/core/Utils.kt

@@ -1,3 +1,5 @@
+package core
+
 import com.google.common.io.BaseEncoding
 import java.util.*
 

tests/contracts/CashTests.kt

@@ -1,3 +1,4 @@
+import core.*
 import org.junit.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith