Handle canonical LF tag names in LfMerge

Now LfMerge can create a CmPossibilityList in FLEx data if it doesn't
already exist, which will allow us to create the custom field that will
store LF tags in FLEx data.

src/LfMerge.Core/DataConverters/CanonicalSources/CanonicalLfTagItem.cs

@@ -0,0 +1,62 @@
+// Copyright (c) 2016-2018 SIL International
+// This software is licensed under the MIT license (http://opensource.org/licenses/MIT)
+using System.Xml;
+using SIL.LCModel;
+
+namespace LfMerge.Core.DataConverters.CanonicalSources
+{
+	public class CanonicalLfTagItem : CanonicalItem
+	{
+		public override void PopulateFromXml(XmlReader reader)
+		{
+			if (reader.LocalName != "item" || string.IsNullOrEmpty(reader.GetAttribute("guid")))
+				return;  // If we weren't on the right kind of node, do nothing
+			GuidStr = reader.GetAttribute("guid");
+			while (reader.Read())
+			{
+				switch (reader.NodeType)
+				{
+				case XmlNodeType.Element:
+					{
+						switch (reader.LocalName)
+						{
+						case "item":
+							if (!string.IsNullOrEmpty(reader.GetAttribute("id")))
+							{
+								Key = reader.GetAttribute("id");
+							}
+							break;
+						case "abbrev":
+							AddAbbrev(reader.GetAttribute("ws"), reader.ReadInnerXml());
+							break;
+						case "term":
+							AddName(reader.GetAttribute("ws"), reader.ReadInnerXml());
+							break;
+						case "def":
+							AddDescription(reader.GetAttribute("ws"), reader.ReadInnerXml());
+							break;
+						}
+						break;
+					}
+				case XmlNodeType.EndElement:
+					{
+						if (reader.LocalName == "item")
+						{
+							if (string.IsNullOrEmpty(Key)) {
+								Key = AbbrevByWs(KeyWs);
+							}
+							reader.Read(); // Skip past the closing element before returning
+							return;
+						}
+						break;
+					}
+				}
+			}
+		}
+
+		protected override void PopulatePossibilityFromExtraData(ICmPossibility poss)
+		{
+			// CanonicalLfTagItem instances don't need anything from ExtraData
+		}
+	}
+}

src/LfMerge.Core/DataConverters/CanonicalSources/CanonicalLfTagSource.cs

@@ -0,0 +1,18 @@
+// Copyright (c) 2016 SIL International
+// This software is licensed under the MIT license (http://opensource.org/licenses/MIT)
+
+namespace LfMerge.Core.DataConverters.CanonicalSources
+{
+	public class CanonicalLfTagSource : CanonicalOptionListSource
+	{
+		public CanonicalLfTagSource()
+			: base("canonical-lf-tags.xml", "item")
+		{
+		}
+
+		public override void LoadCanonicalData()
+		{
+			LoadCanonicalData<CanonicalLfTagItem>();
+		}
+	}
+}

src/LfMerge.Core/DataConverters/CanonicalSources/CanonicalOptionListSource.cs

@@ -36,6 +36,8 @@ public static CanonicalOptionListSource Create(string listCode)
 				return new CanonicalPartOfSpeechSource();
 			else if (listCode == MagicStrings.LfOptionListCodeForSemanticDomains)
 				return new CanonicalSemanticDomainSource();
+			else if (listCode == MagicStrings.LfOptionListCodeForLfTags)
+				return new CanonicalLfTagSource();
 			else
 				return null;
 		}

src/LfMerge.Core/LfMerge.Core.csproj

@@ -59,5 +59,9 @@ See full changelog at https://github.com/sillsdev/LfMerge/blob/master/CHANGELOG.
       <Link>SemDom.xml</Link>
       <LogicalName>SemDom.xml</LogicalName>
     </EmbeddedResource>
+    <EmbeddedResource Include="..\..\data\canonical-lf-tags.xml">
+      <Link>canonical-lf-tags.xml</Link>
+      <LogicalName>canonical-lf-tags.xml</LogicalName>
+    </EmbeddedResource>
   </ItemGroup>
 </Project>

src/LfMerge.Core/MagicStrings.cs

@@ -16,6 +16,7 @@ static MagicStrings()
 			// Option lists that are currently used in LF (as of 2016-03-01)
 			{ LfOptionListCodeForGrammaticalInfo, "Part of Speech" },
 			{ LfOptionListCodeForSemanticDomains, "Semantic Domain" },
+			{ LfOptionListCodeForLfTags, "LF Tags" },
 			{ LfOptionListCodeForAcademicDomainTypes, "Academic Domains" },
 			{ LfOptionListCodeForEnvironments, "Environments" },
 			{ LfOptionListCodeForLocations, "Location" },
@@ -44,6 +45,7 @@ static MagicStrings()
 		// Option lists that are currently used in LF (as of 2016-03-01)
 		public const string LfOptionListCodeForGrammaticalInfo = "grammatical-info";
 		public const string LfOptionListCodeForSemanticDomains = "semantic-domain-ddp4";
+		public const string LfOptionListCodeForLfTags = "lf-entry-tags";
 		public const string LfOptionListCodeForAcademicDomainTypes = "domain-type";
 		public const string LfOptionListCodeForEnvironments = "environments";
 		public const string LfOptionListCodeForLocations = "location";