Preserve Indent/Whitespace from the original XML

Use the XMLNode.Options.nodePreserveAll while creating the XMLDocument object.

This resolves #2

xliff-tool/Document.swift

@@ -42,7 +42,7 @@ class Document: NSDocument {
 
     class func getXMLDocument(from data: Data) throws -> XMLDocument {
         do {
-            return try XMLDocument(data: data, options: Int(XMLNode.Options.documentTidyXML.rawValue))
+            return try XMLDocument(data: data, options: Int(XMLNode.Options.nodePreserveAll.rawValue))
         } catch (let error as NSError) {
             throw NSError(domain: NSCocoaErrorDomain, code: NSFileReadCorruptFileError, userInfo: [
                 NSLocalizedDescriptionKey: NSLocalizedString("Could not read file.", comment: "Read error description"),

xliff-toolTests/xliff_toolTests.swift

@@ -7,6 +7,15 @@
 //
 
 import XCTest
+@testable import XLIFFTool
+
+extension String {
+    var lines:[String] {
+        var result:[String] = []
+        enumerateLines{ (line, _) in result.append(line) }
+        return result
+    }
+}
 
 class xliff_toolTests: XCTestCase {
 
@@ -43,6 +52,18 @@ class xliff_toolTests: XCTestCase {
         XCTAssertEqual(xliffFile.files[0].items.first!.elements(forName: "source").first!.stringValue, "Text Cell")
     }
 
+    // check of the xml file is saved while preserving all whitespace/line breaks from the original
+    func testSaveFormatting() {
+        let data = xliffDocument.xmlData
+        if let content = String(data: data, encoding: .utf8),
+            let originalContent = String(data: xliffData, encoding: .utf8) {
+            // check if the 3. last line is equal
+            XCTAssertEqual(
+                content.lines[content.lines.count - 3],
+                originalContent.lines[originalContent.lines.count - 3] )
+        }
+    }
+
     func testPerformanceExample() {
         // This is an example of a performance test case.
         self.measure {