! http: add small extensions to Uri model

Specifically:
- additional `charset` parameter on `Uri.Host.apply` and `Uri.Query.apply`
- new method: Uri.Query::toMap

spray-http/src/main/scala/spray/http/Uri.scala

@@ -164,7 +164,7 @@ object Uri {
   def from(scheme: String = "", userinfo: String = "", host: String = "", port: Int = 0, path: String = "",
            query: Query = Query.Empty, fragment: Option[String] = None,
            mode: Uri.ParsingMode = Uri.ParsingMode.Relaxed): Uri =
-    apply(scheme, Authority(Host(host, mode), normalizePort(port, scheme), userinfo), Path(path), query, fragment)
+    apply(scheme, Authority(Host(host, UTF8, mode), normalizePort(port, scheme), userinfo), Path(path), query, fragment)
 
   /**
    * Parses a string into a normalized absolute URI as defined by http://tools.ietf.org/html/rfc3986#section-4.3.
@@ -270,7 +270,7 @@ object Uri {
       def toOption = None
       def render[R <: Rendering](r: R): r.type = r
     }
-    def apply(string: String, mode: Uri.ParsingMode = Uri.ParsingMode.Relaxed): Host =
+    def apply(string: String, charset: Charset = UTF8, mode: Uri.ParsingMode = Uri.ParsingMode.Relaxed): Host =
       if (!string.isEmpty) {
         val parser = new UriParser(string, UTF8, mode)
         import parser._
@@ -416,6 +416,11 @@ object Uri {
         if (q.isEmpty) result else fetch(q.tail, if (q.key == key) q.value :: result else result)
       fetch(this)
     }
+    def toMap: Map[String, String] = {
+      @tailrec def append(map: Map[String, String], q: Query): Map[String, String] =
+        if (q.isEmpty) map else append(map.updated(q.key, q.value), q.tail)
+      append(Map.empty, this)
+    }
     def toMultiMap: Map[String, List[String]] = {
       @tailrec def append(map: Map[String, List[String]], q: Query): Map[String, List[String]] =
         if (q.isEmpty) map else append(map.updated(q.key, q.value :: map.getOrElse(q.key, Nil)), q.tail)
@@ -445,16 +450,16 @@ object Uri {
      * Empty strings will be parsed to `("", "") +: Query.Empty`
      * If you want to allow for Query.Empty creation use the apply overload taking an `Option[String`.
      */
-    def apply(string: String, mode: Uri.ParsingMode = Uri.ParsingMode.Relaxed): Query = {
-      val parser = new UriParser(string, UTF8, mode)
+    def apply(string: String, charset: Charset = UTF8, mode: Uri.ParsingMode = Uri.ParsingMode.Relaxed): Query = {
+      val parser = new UriParser(string, charset, mode)
       import parser._
       complete("Query", query)
       _query
     }
     def apply(input: Option[String]): Query = apply(input, Uri.ParsingMode.Relaxed)
     def apply(input: Option[String], mode: Uri.ParsingMode): Query = input match {
       case None         ⇒ Query.Empty
-      case Some(string) ⇒ apply(string, mode)
+      case Some(string) ⇒ apply(string, mode = mode)
     }
     def apply(kvp: (String, String)*): Query =
       kvp.foldRight(Query.Empty: Query) { case ((key, value), acc) ⇒ Cons(key, value, acc) }

spray-http/src/test/scala/spray/http/UriSpec.scala

@@ -220,7 +220,7 @@ class UriSpec extends Specification {
   }
 
   "Uri.Query instances" should {
-    def parser(mode: Uri.ParsingMode): String ⇒ Query = Query(_, mode)
+    def parser(mode: Uri.ParsingMode): String ⇒ Query = Query(_, mode = mode)
     "be parsed and rendered correctly in strict mode" in {
       val test = parser(Uri.ParsingMode.Strict)
       test("") === ("", "") +: Query.Empty