Remove Typescript file from build

[DanielKucal]

There is .ts file in npm package what can cause troubles with some unspecified Typescript compiler config: https://stackoverflow.com/questions/44377617/unable-to-find-typings-d-ts-and-declare-modules-in-angular-2-typescript-app/44380574#44380574
I suggest to add .npmignore file with the following contents:

*.ts
!*.d.ts
.DS_Store
.DS_Store?
gulpfile.js
/node_modules/*

Thanks in advance for cooperation.

[jvincilione]

This needs to be done, angular 5 won't build properly with these files.