chore(build): update to Angular v5.2 and update peer-dep requirements

[CaerusKaru]

• Update to Angular v5.2 and TypeScript v2.6
• Update build config to conform with fix: too strict peer dependency of angular components#9355
• Update travis to node 8 and npm latest
• Bring package build patterns in line with angular/material2
• Enable strictNullChecks and refactor as necessary

Succeeds PR #560

Fixes #559

[devversion]

Would it be possible to also update the publish-build-artifacts.sh script? There has been a critical fix to the publish script, that should be fixed on flex-layout as well (to guarantee a less flakier CI)

• See: https://github.com/angular/material2/blob/master/scripts/deploy/publish-build-artifacts.sh

[CaerusKaru]

Looks like @ThomasBurleson beat me to it with fe877c9

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