Macros: Made internal methods static and .c-file local

Lot of methods in the mecros.c is for internal use only, and shouldn't be
exposed. Those methods also has an undocumented and non-public API, which makes
them dangerous for use in broker modules, and isn't used in nagios.

For example, char **output is set to the output string in many methods, but
depending on the int macro_type, this should be free:ed afterwards, which isn't
returned uniformly from the methods, so an up-to-date lookup table is needed if
the system shouldn't leak memory.

Signed-off-by: Max Sikström <msikstrom@op5.com>