Does not support ES2015

[aaronroberson]

When I run this on a file that has import the following error is thrown:

Error: Line 1: Unexpected reserved word
    at throwError (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1156:21)
    at throwUnexpected (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1204:17)
    at parsePrimaryExpression (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1567:16)
    at /usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:3609:38
    at trackLeftHandSideExpressionAllowCall (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:3504:61)
    at parsePostfixExpression (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1703:20)
    at /usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:3609:38
    at parseUnaryExpression (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1784:16)
    at /usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:3609:38
    at parseMultiplicativeExpression (/usr/local/lib/node_modules/jsc/node_modules/complexity-report/node_modules/esprima/esprima.js:1790:20)