Cleanup deprecated methods.

Noticed a handful of deprecated methods and minor warnings while looking around.
Replaces with recommended methods

multiplatform-crypto-api/src/commonMain/kotlin/com/ionspin/kotlin/crypto/Api.kt

@@ -3,13 +3,15 @@ package com.ionspin.kotlin.crypto
 import com.ionspin.kotlin.crypto.hash.MultipartHash
 import com.ionspin.kotlin.crypto.hash.encodeToUByteArray
 import com.ionspin.kotlin.crypto.util.toHexString
+import kotlin.jvm.JvmInline
 
 /**
  * Created by Ugljesa Jovanovic
  * ugljesa.jovanovic@ionspin.com
  * on 23-Jun-2020
  */
-inline class EncryptableString(val content: String) : Encryptable<EncryptableString> {
+@JvmInline
+value class EncryptableString(val content: String) : Encryptable<EncryptableString> {
     override fun toEncryptableForm(): UByteArray {
         return content.encodeToUByteArray()
     }

multiplatform-crypto-api/src/commonMain/kotlin/com/ionspin/kotlin/crypto/symmetric/XChaCha20.kt

@@ -44,4 +44,4 @@ interface XChaCha20KeyProvider {
     fun generateNewKey() : XChaCha20.Key
 
     fun createFromUByteArray(uByteArray: UByteArray) : XChaCha20.Key
-}
+}

multiplatform-crypto-api/src/commonMain/kotlin/com/ionspin/kotlin/crypto/util/CryptoUtil.kt

@@ -8,13 +8,13 @@ package com.ionspin.kotlin.crypto.util
 val _emit = IntArray(0)
 
 fun UByteArray.overwriteWithZeroes() {
-    for (i in 0 until size) {
+    for (i in indices) {
         this[i] = 0U
     }
 }
 
 fun UIntArray.overwriteWithZeroes() {
-    for (i in 0 until size) {
+    for (i in indices) {
         this[i] = 0U
     }
 }

multiplatform-crypto-api/src/commonMain/kotlin/com/ionspin/kotlin/crypto/util/StringUtil.kt

@@ -7,22 +7,22 @@ package com.ionspin.kotlin.crypto.util
  */
 fun Array<Byte>.hexColumsPrint() {
     val printout = this.map { it.toString(16) }.chunked(16)
-    printout.forEach { println(it.joinToString(separator = " ") { it.toUpperCase() }) }
+    printout.forEach { println(it.joinToString(separator = " ") { it.uppercase() }) }
 }
 
 fun Array<UByte>.hexColumsPrint(chunk : Int = 16) {
     val printout = this.map { it.toString(16).padStart(2, '0') }.chunked(chunk)
-    printout.forEach { println(it.joinToString(separator = " ") { it.toUpperCase() }) }
+    printout.forEach { println(it.joinToString(separator = " ") { it.uppercase() }) }
 }
 
 fun UByteArray.hexColumsPrint(chunk : Int = 16) {
     val printout = this.map { it.toString(16).padStart(2, '0') }.chunked(chunk)
-    printout.forEach { println(it.joinToString(separator = " ") { it.toUpperCase() }) }
+    printout.forEach { println(it.joinToString(separator = " ") { it.uppercase() }) }
 }
 
 fun Array<ULong>.hexColumsPrint(chunk: Int = 3) {
     val printout = this.map { it.toString(16) }.chunked(chunk)
-    printout.forEach { println(it.joinToString(separator = " ") { it.toUpperCase() }) }
+    printout.forEach { println(it.joinToString(separator = " ") { it.uppercase() }) }
 }
 
 fun String.hexStringToTypedUByteArray() : Array<UByte> {