Constructor parameter in docs but not code

[lesamouraipourpre]

The ambient_pressure constructor parameter is listed in the docs but it is not implemented in the code.

Should this be removed from the docs or added to the code?
I can submit a PR for either preference.

[ladyada]

woops yeah please remove that line from the dox - it was a copy paste error (we have a different funciton to set the ambient pressure)