Pull in basic HMM storing capabilities from SWISSMODEL

modules/seq/base/doc/seq.rst

modules/seq/base/pymod/CMakeLists.txt

modules/seq/base/pymod/export_hmm.cc

modules/seq/base/pymod/wrap_seq.cc

modules/seq/base/src/CMakeLists.txt

modules/seq/base/src/hmm.cc

modules/seq/base/src/hmm.hh

modules/seq/base/tests/CMakeLists.txt

modules/seq/base/tests/test_hmm.cc

modules/seq/base/tests/testfiles/test_hmm.hhm