Fix namespace pollution by num module

[rhdtownsend]

The num module currently re-exports a number of variables defined in other modules (e.g., const). This is bad practice, and should be an easy fix.

[pmocz]

@rhdtownsend could you give some examples and where to find them in the source?

[rhdtownsend]

Sure -- if you take a look in num/public/num_lib.f, you'll see there are no private/public statements before the contains statement. This means that all of the symbols e.g. from const_def are re-exported by num.

What we should have, before the contains statement, is

private
public :: func1
public :: func2

...where func1, func2, etc are the names of the routines defined in num_lib.