Enable conditional compilation

Closes #36 (closed)

With this MR we added the capability of conditional compilation. Two cmake options were added, that are enabled by default:

1. -DFORCES_WITH_OPTIMIZATION=[ON|OFF]: include all modules used for optimization (sce, mcmc, anneal, dds, errormeasures, likelihood, opt_functions, cost, optimization_types, optimization_utils)
2. -DFORCES_WITH_NETCDF=[ON|OFF]: include all modules using NetCDF (netcdf, ncwrite, ncread)
   • Here, mo_mcmc throws an error if you want to have a tmp_file written out.
   • This option can be used to drop the NetCDF dependency, if netcdf io is not needed for your program