ORG rework, part 1

This is the first step toward changing the address region map from a
linear list to a hierarchy.  See issue #107 for the plan.

The AddressMap class has been rewritten to support the new approach.
The rest of the project has been updated to conform to the new API,
but feature-wise is unchanged.  While the map class supports
nested regions with explicit lengths, the rest of the application
still assumes a series of non-overlapping regions with "floating"
lengths.

The Set Address dialog is currently non-functional.

All of the output for cc65 changed because generation of segment
comments has been removed.  Some of the output for ACME changed as
well, because we no longer follow "* = addr" with a redundant
pseudopc statement.  ACME and 65tass have similar approaches to
placing things in memory, and so now have similar implementations.

PluginCommon/PluginManager.cs

@@ -179,11 +179,12 @@ namespace PluginCommon {
         /// Invokes the Prepare() method on all active plugins.
         /// </summary>
         /// <param name="appRef">Reference to host object providing app services.</param>
+        /// <param name="spanLength">Length of data spanned by address map.</param>
         /// <param name="addrEntries">Serialized AddressMap entries.</param>
         /// <param name="plSyms">SymbolTable contents, converted to PlSymbol.</param>
-        public void PreparePlugins(IApplication appRef,
+        public void PreparePlugins(IApplication appRef, int spanLength,
                 List<AddressMap.AddressMapEntry> addrEntries, List<PlSymbol> plSyms) {
-            AddressMap addrMap = new AddressMap(addrEntries);
+            AddressMap addrMap = new AddressMap(spanLength, addrEntries);
             AddressTranslate addrTrans = new AddressTranslate(addrMap);
             foreach (KeyValuePair<string, IPlugin> kvp in mActivePlugins) {
                 IPlugin ipl = kvp.Value;