Refactor range_eql() func in rangec.c
Add Range#eql? method test.
Fix Range#==
Fix some signed unsigned warnings, int to size_t.
Change int to size_t.
Change int to size_t
Merge pull request #1322 from suzukaze/refactor-range-c

Refactor range_eql() func in rangec.c and add Range#eql? method test.
Merge pull request #1324 from h2so5/fix-range-equal

Fix Range#==
Merge pull request #1325 from carsonmcdonald/unsignedfixes

Fix a few unsigned signed comparison warnings