Try improving the TesterConfig initialization

[kbouchard]

Right now, when we configure Tester for a project, we must pass the enzyme package otherwise, we end up using 2 enzyme version and it throws errors and create mismatches.

We should contact Enzyme directly to:

• Ask wether there is a better way of doing this.
  ** If there is, improve.
  ** If not, make that requirement prominent in the docs.

Configuration example

import enzyme from 'enzyme';

// Adapt enzyme to the proper React version.

TesterConfig.configure(enzyme, { ... });