added how to force libffi include/lib path
Merge pull request #17 from schmurfy/patch-1

added how to force libffi include/lib path
added helper function for errno / strerror
allow access to the fields object in structrures

helps mimic how ruby-ffi works when working with
structures.
added UInt64.divide
Merge pull request #18 from schmurfy/errno

added helper function for errno / strerror
Merge pull request #19 from schmurfy/struct_helper

allow access to the fields object in structrures
added test for UInt64.divide
commented unused function
Merge pull request #21 from schmurfy/cleanup

commented unused function
Merge pull request #20 from schmurfy/uin64_divide

added UInt64.divide