Significant rewrite to use 4koma, OkHttp, PackwizPath; fixing several issues

Github release plugin, Kotlin, Okio and OkHttp updated
Toml4j removed and replaced with 4koma - improves null safety, immutability, TOML compliance
kotlin-result removed (I don't think it was used anyway)
SpaceSafeURI replaced with PackwizPath which handles special characters much better (fixes #5)
Fixed directory traversal issues
Hashing system rewritten for better type safety and cleaner code
Download mode changed to use an enum
Request system completely rewritten; now uses OkHttp for HTTP requests (fixes #36, fixes #5)
Added request interceptor which retries requests (fixes #4)
Removed: support for extracting packs from zip files (and Github zipballs)
Cleaner exceptions; more improvements pending (in particular showing request failure causes)
Improved speed of cancelling in-progress downloads
Better support for installing from local files (no file: URI required; though it is still supported)
Various code cleanup changes

src/main/kotlin/link/infra/packwiz/installer/ui/IUserInterface.kt

@@ -41,6 +41,16 @@ interface IUserInterface {
 
 	var optionsButtonPressed: Boolean
 	var cancelButtonPressed: Boolean
+	var cancelCallback: (() -> Unit)?
 
 	var firstInstall: Boolean
+
+}
+
+inline fun <T> IUserInterface.wrap(message: String, inner: () -> T): T {
+	return try {
+		inner.invoke()
+	} catch (e: Exception) {
+		showErrorAndExit(message, e)
+	}
 }

src/main/kotlin/link/infra/packwiz/installer/ui/cli/CLIHandler.kt

@@ -11,9 +11,12 @@ import kotlin.system.exitProcess
 class CLIHandler : IUserInterface {
 	@Volatile
 	override var optionsButtonPressed = false
+	// TODO: treat ctrl+c as cancel?
 	@Volatile
 	override var cancelButtonPressed = false
 	@Volatile
+	override var cancelCallback: (() -> Unit)? = null
+	@Volatile
 	override var firstInstall = false
 
 	override var title: String = ""

src/main/kotlin/link/infra/packwiz/installer/ui/gui/GUIHandler.kt

@@ -28,7 +28,10 @@ class GUIHandler : IUserInterface {
 		set(value) {
 			optionalSelectedLatch.countDown()
 			field = value
+			cancelCallback?.invoke()
 		}
+	@Volatile
+	override var cancelCallback: (() -> Unit)? = null
 	var okButtonPressed = false
 		set(value) {
 			optionalSelectedLatch.countDown()