Updated ClusterTPA

Updated ClusterTPA to use Integer for dist paramater instead, because Extended was a little bit too precise/accurate.
Also, added rounding for distance calculation parts, just like SplitTPA does - this way, keeping the results 100% identical with both methods!
Update lpexportedmethods.inc

Updated dist parameter variable from Extended to Integer.
Update lp_tpa.inc

Updated dist parameter variable from Extended to Integer.
Update psexportedmethods.inc

Updated ClusterTPA's dist parameter variable from Extended to Integer.
Update tpa.inc

Updated ClusterTPA's dist parameter variable from Extended to Integer.
Changed line 77

I forgot to change this one too:

function ClusterTPA(const TPA: TPointArray; dist: Extended): T2DPointArray;

=>

function ClusterTPA(const TPA: TPointArray; dist: Integer): T2DPointArray;
Fixed descriptions for Clustering methods

ClusterTPAEx is alternative for SplitTPAEx and ClusterTPA is alternative for SplitTPA - these were opposite, so I changed em to how they should be. :)
Merge pull request #242 from Janilabo/master

ClusterTPA Updated