change default tsc options. use `--target es6 --module commonjs --exp…

[vvakame]

…erimentalDecorators`

[vvakame]

The job exceeded the maxmimum time limit for jobs, and has been terminated. in travis ci...
I'll ignore it. We can't full test this tool in Travis CI now...

@DefinitelyTyped/contributors Can I merge this PR?
I want to use --target es6 default in DT repo.
Promise becomes standard API and used by a lot of scene.
now, definition-tester can use --target es6 with .tscparams, but it is not easy for understanding.
If you want to use --target es5, you should put .tscparams after this change released.

next step

1. release new definition-tester.
2. bump definition-tester version in DT repo & fix ci error.
3. release to master/HEAD of DT repo.

[johnnyreilly]

Fine with me

[horiuchi]

I think that's better. 👍

And so, this line is not needed: https://github.com/DefinitelyTyped/definition-tester/pull/15/files#diff-791ec60a6e04d0003ab8d665e2133f42R42

[vvakame]

I'll merge this PR after dinner. (It is an hours ago)

[evmar]

How do I use DefinitelyTyped definitions when targeting es5? It seems this change caused you to drop lots of reference to Promise<>.

[alexeagle]

If you target es5 then you need to include typings like https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/es6-promise/es6-promise.d.ts when you execute tsc.
Because of Duplicate identifiers, having these referenced from other libraries made it impossible to target --es6 due to microsoft/TypeScript#3215 (which is now assigned)