Apply hotfix to support SSR (Fixes #92)

[Kaptard]

Added this direct hotfix for window not being available server-sided. It's been 9 months since the PR for this has been proposed, so I think that 'temporary' fix in the readme should be implemented directly for the time being.

Functionally, this does the same as the proposed readme fix:

• Puts the Hammer.js import in a try/catch block
• If an error occurs (-> window is not defined), it assigns an empty stub to Hammer instead

It's not the most beautiful fix, but better than workarounds with webpack that don't work on certain setups.

[homerjam]

+1

[dr1v3]

+1

[KevisLuo]

+1

[MichaelSchober]

+1

[marco-gattelli]

+1