Use library name as filename, as Idea changes to it anyway

While at it, replace replaces (sic) with replaceAll regexp.

src/main/scala/org/sbtidea/IdeaProjectDescriptor.scala

@@ -129,7 +129,7 @@ class IdeaProjectDescriptor(val projectInfo: IdeaProjectInfo, val env: IdeaProje
       librariesDir.mkdirs
       for (ideaLib <- projectInfo.ideaLibs) {
         // MUST all be _
-        val filename = ideaLib.id.replace('.', '_').replace('-', '_') + ".xml"
+        val filename = ideaLib.name.replaceAll("[:\\.\\s-]", "_") + ".xml"
         saveFile(librariesDir, filename, libraryTableComponent(ideaLib))
       }