Build problems on Ubuntu and MacOSX

[peterstockwell]

Following the README instructions for building TPMCalculator from source fails for a couple of reasons:

1: setting LDFLAGS="-L $BAMTOOLS_DIR/lib64 -Wl,-rpath,$BAMTOOLS_DIR/lib64" is not correct - the build process for bamtools does not generate a lib64 directory, rather libbamtools.a is in the lib directory.

2: the TPMCalculator make fails since the final build command contains -L../../bamtools/lib whereas the instructions have the default dir as /TPMCalculator from where the command should be -L../bamtools/lib.