3.3

Hi guys,

please have a look at the changes I made to implement the Immersed-Boundary Method in Espresso. I tried to keep the number of modifications to Espresso to the absolute minimum, prefering to add new files instead of modifying existing ones, wherever possible.
A number of tests were made and it seems to be working fine.
Please comment on whether you find the structure such that it could possibly be merged into the next Espresso version.

Best greetings,

  Stephan