Fixes #225 - Use a properly defined user agent

* Set a proper user agent
* Add fallback when UA comes out nil
* Remove unused Bundle extension
* Return nil when asciification fails
* Add whitespace handling and further emoji test case
* Explicitly check if string is already in ASCII
* Rename factory to builder
* Use allSatisfy instead of reduce
* Use key path syntax

UnitTests/Sources/StringTests.swift

@@ -0,0 +1,61 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import XCTest
+
+@testable import ElementX
+
+class StringTests: XCTestCase {
+    func testEmptyIsAscii() {
+        XCTAssertTrue("".isASCII)
+    }
+    
+    func testSpaceIsAscii() {
+        XCTAssertTrue("".isASCII)
+    }
+
+    func testJohnnyIsAscii() {
+        XCTAssertTrue("johnny".isASCII)
+    }
+    
+    func testJöhnnyIsNotAscii() {
+        XCTAssertFalse("jöhnny".isASCII)
+    }
+    
+    func testJ🅾️hnnyIsNotAscii() {
+        XCTAssertFalse("j🅾️hnny".isASCII)
+    }
+
+    func testAsciiStaysAscii() {
+        XCTAssertEqual("johnny".asciified(), "johnny")
+    }
+    
+    func testÖBecomesO() {
+        XCTAssertEqual("jöhnny".asciified(), "johnny")
+    }
+    
+    func testÅBecomesA() {
+        XCTAssertEqual("jåhnny".asciified(), "jahnny")
+    }
+    
+    func test1️⃣2️⃣3️⃣Becomes123() {
+        XCTAssertEqual("1️⃣2️⃣3️⃣".asciified(), "123")
+    }
+    
+    func testStripsTheHeartbreakHotel() {
+        XCTAssertEqual("Heartbreak Hotel 🏩".asciified(), "Heartbreak Hotel")
+    }
+}