Proposal: Replace CMake with a Makefile

The process of using CMake to build the model is a little kludgy, and the project isn't complicated enough that we _need_ the cross-platform magic that CMake could help with. Even if this Makefile/build process gets changed, at least this shows that its not _too_ difficult to write one.

Executables are put into ```meltmodel/bin```, and intermediate compilation products (object files) are stored in ```meltmodel/build```.  After compiling, its safe to delete the ```build```folder, but its nice to have the object files outside of the source directory.

This file needs work and **should not be merged** into the release branch yet.

How it works:
+ Clone the model
```
    $ git clone https://github.com/fmuzf/meltmodel.git
    $ cd meltmodel
    $ git checkout makefile
```

+ Compile everything
```
  $ make all
```

+ Compile the Models
   ```
   $ make models
   ```
  Binaries for debam and detim will be located in ```bin```

+ Compile the utility programs (shading, ascigrid etc.)
```
    $ make utils
```
  Again, binaries will be locates in ```bin```.

+ Compile a single executeable (debam, detim, ascigrid, etc)
```
    $ make debam
```