Issue50 Afloor + updating replaceable parameter into replaceable

1) A_floor is now a parameter in embeddedpipe. It has been removed from RadiantSlabChar.mo. Examples and nakedtabs have been updated according to this new definition.

2) Some 'replaceable parameters' still had to be changed into 'replaceable'. @rubenbaetens I thought you said this was already ok in the Annex60 branch? Can you confirm this change is ok?

Note that many unit tests seem to fail, possibly due to the new TMY3 reader.

This line should be:RadSlaCha.d_a - 2*RadSlaCha.s_r (factor 2 for the thickness of the pipe wall).

If we decide to compute the pressure losses we should take the pipe bends into account.