More ECMAScript 2015 errors

[bugs181]

String Interpolation:

console.log(`Status: ${status}`)

Result:

$ node-theseus test
exception during parsing ..../test.js Error: Line 6: Unexpected token ILLEGAL
    at throwError (/usr/local/lib/node_modules/node-theseus/node_modules/fondue/node_modules/falafel/node_modules/esprima/esprima.js:1161:21)
    at advance (/usr/local/lib/node_modules/node-theseus/node_modules/fondue/node_modules/falafel/node_modules/esprima/esprima.js:1089:9)

**Arrow functions:**

setTimeout(_ => { }, 2000)

Result:

$ node-theseus test
exception during parsing ..../test.js Error: Line 12: Unexpected token >
    at throwError (/usr/local/lib/node_modules/node-theseus/node_modules/fondue/node_modules/falafel/node_modules/esprima/esprima.js:1156:21)
    at throwUnexpected (/usr/local/lib/node_modules/node-theseus/node_modules/fondue/node_modules/falafel/node_modules/esprima/esprima.js:1213:9)