Using typescript 2.1.4 object spread operator

[damienpontifex]

PR checklist

• Read the contribution guildelines.
• Ran the shell/batch script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates)
• Filed the PR against the correct branch: master for non-breaking changes and 2.3.0 branch for breaking (non-backward compatible) changes.

Description of the PR

(details of the change, additional tests that have been done, reference to the issue for tracking, etc)

Resolves #4407 by replacing extendObj function by Typescript 2.1.4s object spread operator functionality

[wing328]

@damienpontifex thanks for the PR. Please run the following to update the Petstore samples so that CIs can verify the change.

./bin/typescript-node-petstore-all.sh
./bin/typescript-angular2-petstore-all.sh
./bin/typescript-angular-petstore.sh

[damienpontifex]

Thanks @wing328 I've run the scripts and squashed the updated samples and template changes into a single commit again.

[wing328]

@damienpontifex thanks but Travis reports issue with the TS Angular Petstore client and here is part of the error message:

API/Client/PetApi.ts(41,64): error TS1136: Property assignment expected.
API/Client/PetApi.ts(41,71): error TS1005: ':' expected.
API/Client/PetApi.ts(51,39): error TS1136: Property assignment expected.
API/Client/PetApi.ts(51,61): error TS1136: Property assignment expected.
API/Client/PetApi.ts(67,64): error TS1136: Property assignment expected.
API/Client/PetApi.ts(67,71): error TS1005: ':' expected.
API/Client/PetApi.ts(82,39): error TS1136: Property assignment expected.
API/Client/PetApi.ts(82,61): error TS1136: Property assignment expected.
API/Client/PetApi.ts(96,64): error TS1136: Property assignment expected.
API/Client/PetApi.ts(96,71): error TS1005: ':' expected.

Ref: https://s3.amazonaws.com/archive.travis-ci.org/jobs/185324798/log.txt

[damienpontifex]

@wing328 fixed up all the required changes in the samples and moved the sample typescript dependencies up to 2.1.4. Also moved them to use declaration files from npm to align with updated TypeScript recommendations of handling type definitions

[wing328]

@damienpontifex If I understand correctly, the change is not backward compatible with the existing TS clients so please submit the PR against the 2.3.0 branch instead.

[damienpontifex]

@wing328 see #4562 for better backwards compatibility achieving the same results. This PR can be closed in favour of that as desired.

[wing328]

Closed via #4562