Fix loading error on Ruby 1.8.7 by renaming the C++ extension to fox1…

…6_c.

Before commit af54382 loading order of fox16.so and fox16.rb was irrelevant.
But now fox16.rb must be called, in order to load ruby files to the C++
extension. Renaming the C++ extension ensures, that fox16.rb is called first.

.gitignore

@@ -2,13 +2,13 @@ doap.rdf
 *.tmproj
 doc/api
 users_guide/*.html
-ext/fox16/*_wrap.cpp
-ext/fox16/*.o
-ext/fox16/conftest.dSYM
-ext/fox16/include/inlinestubs.h
-ext/fox16/librb.c
-ext/fox16/fox16.bundle
-ext/fox16/mkmf.log
+ext/fox16_c/*_wrap.cpp
+ext/fox16_c/*.o
+ext/fox16_c/conftest.dSYM
+ext/fox16_c/include/inlinestubs.h
+ext/fox16_c/librb.c
+ext/fox16_c/fox16.bundle
+ext/fox16_c/mkmf.log
 lib/fox16/kwargs.rb
 fox-includes/diffs.py
 fox-includes/diffs.txt