Simplify the API for emitting code from the Program instance.

src/harness/fourslash.ts

@@ -2216,7 +2216,7 @@ module FourSlash {
         if (errors.length > 0) {
             throw new Error('Error compiling ' + fileName + ': ' + errors.map(e => e.messageText).join('\r\n'));
         }
-        program.emitFiles();
+        program.emit();
         result = result || ''; // Might have an empty fourslash file
 
         // Compile and execute the test

src/harness/harness.ts

@@ -1086,7 +1086,7 @@ module Harness {
                 // only emit if there weren't parse errors
                 var emitResult: ts.EmitResult;
                 if (!isEmitBlocked) {
-                    emitResult = program.emitFiles();
+                    emitResult = program.emit();
                 }
 
                 var errors: HarnessDiagnostic[] = [];

src/harness/projectsRunner.ts

@@ -131,7 +131,7 @@ class ProjectRunner extends RunnerBase {
             var sourceMapData: ts.SourceMapData[] = null;
             if (!errors.length) {
                 errors = program.getTypeCheckerDiagnostics();
-                var emitResult = program.emitFiles();
+                var emitResult = program.emit();
                 errors = ts.concatenate(errors, emitResult.diagnostics);
                 sourceMapData = emitResult.sourceMaps;