Modularization

Major changes in 0e8602f4. Routines in the bolam.F90 file have been exported to various external "_mod.F90" files.

The bolam.F90 now only contains the main program, and we have this new module files:

• radiation_mod.F90: contains radiative routines (aerdef, radintec, ..)
• dynamics_mod.F90: contains routines defining advection and diffusion
• physics_mod.F90: contains microphysics, convection, block and orog drag parametrizations
• surface_mod.F90: contains routines related to soil and surface processes (snow, veg), including the update of the surface boundary conditions
• io_utils_mod.F90: routines needed for input/output of mhf files. Most of these to be replaced..
• mpi_utils_mod.F90: routines that distribute fields (collect/disperse) and communicate between nodes (u_ghost). For simplicity I also put here routines related to filtering/interpolation, which are needed by many other modules.
• utils_mod.F90: short module containing a few general purpose routines (interp, tridiag, ..) needed by many modules.

Further tasks to be done:

• check consistency and optionally move routines from the "assigned" module;
• also export to the respective modules parts of the main program;

The makefile templates - both for coupled and uncoupled - have been updated. The test run was successful with 60c90ea5.

To be checked before merging to pseudo-main (and main?).