Rename STATICLIB macro to resolve natpmp/miniupnp conflict

Same macro name is used in both natpmp and miniupnp libraries so it's
impossble to link one statically and another dynamically. This patch
renames the macro to have library-specific name.
Rename LIBSPEC macro to resolve natpmp/miniupnp conflict

Same macro name is used in both natpmp and miniupnp libraries so it's
impossble to link one statically and another dynamically. This patch
renames the macro to have library-specific name.
Merge pull request #77 from mikedld/miniupnp-staticlib

Rename STATICLIB macro to resolve natpmp/miniupnp conflict