lib/PCR/Primer3.pm
Converted module to use Moose
Added BUILD method which runs immediately after object creation to check that
the primer3 binary and config directory exist.
Changed subroutine setAmpInput to conform to primer3 v2.3 and above
Changed subroutine primer3 to create the primers first and then the primer pair.
Allows left_ and right_primer attributes to be read-only.
New File: Test file for Primer3.pm.
New File: Primer3 config file for t/primer3.t