Ignore .vs folder in template.json

More recent versions of MonoDevelop create a .vs folder. If a
.template.config folder is created for the solution, so this folder
is next to the .vs folder, then when you try to create a new project
from the template you will get a sharing violation error:

Could not create template. Id='MyTemplate.Test' CreateFailed
Error while processing file /.vs/Test/xs/sqlite3/db.lock
Sharing violation on path Test/.vs/Test/xs/sqlite3/db.lock

To workaround this the template.json file now includes a sources
section that excludes the .vs directory and all its files.

Fixes #4

src/MonoDevelop.TemplateCreator/ConfigurationFiles/template.json

@@ -16,6 +16,17 @@
 	"sourceName": "${SourceName}",
 	"guids": [
 	],
+	"sources": [
+		{
+			"modifiers": [
+				{
+					"exclude": [
+						".vs/**/*"
+					]
+				}
+			]
+		}
+	],
 	"primaryOutputs": [
 	]
 }