Make compatible with TypeScript 2.1

[flying-sheep]

When installing TypeScript 2.1, tests start to fail. This is why travis is currently failing for every PR.

We should handle the AST it produces.

[soda0289]

I will take a look at some of these tests.

[JamesHenry]

I'm looking into this now. I will be putting together a list of updates needed on this issue:

• Update devDependency and peerDependency to ~2.1.5

Updates relating to existing tests which break when updating the version:

• exclude new modifierFlagsCache property during TSNode auto-conversion
• update detection for static modifier. There is now ts.ModifierFlags.
• TS SyntaxKind.SpreadElementExpression has been changed. Now there is SyntaxKind.SpreadElement and SyntaxKind.SpreadAssignment
• JSDoc-style comment handling has changed and is causing all of the tokens to be skipped in one test case. This was also the behaviour highlighted in Parser does not handle jsdoc well #118 by @jtheoof

The WIP is available on the branch ts-2.1, it can't be merged until all the work is completed because the move from TS 2.0.x to TS 2.1.x is a breaking change for this parser.

[JamesHenry]

Just FYI, I have asked for some feedback from the TypeScript on the final point, as I would love to get this over the line:

microsoft/TypeScript#13519

[JamesHenry]

This has been confirmed as a TypeScript bug, so unfortunately the upgrade to 2.1.x is blocked for now