SystemJS 0.18.12

Features

• Package map now supports package self-aliasing (#410)
• Some experimental features (9427408, 06f5d77)

Bug Fixes

• GLOBAL defined for CommonJS (#710)
• builderExecute SystemJS builder fix (9aea7a3)
• Fix interaction bug between defaultExtension and defaultJSExtension for direct package name requires with no main (b7abc2c, f4a1850)