v7.4 Support

T4Utils2 now officially supports both TerminalFour v7.4 and v8.1. Here's what's changed:

• The Gulp build system now compiles 2 versions of the library (for TerminalFour v7.4 and v8.1)
  • The main gulpfile.js now uses a build module to simplify and bootstrap library compilation code
• The ordinalIndicators module now uses replaceable strings for any v7.1/v8.1 API discrepancies
  • These replaceable strings are changed to the correct API calls during the build process
• The elementInfo module has had undefined variable issues fixed
• The media module's getImageVariantsIds method is now wrapped in a T4Utils.contextIsContent conditional