Merge pull request #5 from postmodern/master

New "module_name" instead of "ruby_module" in README.
Renamed FFIGen to FFI::Gen and moved files.
Update master
Improved comment processing.
Renamed directories.
Added headers for test so that they should run on every machine.
Added new libssh2 test.
More processed defines.
Added warnings for unsupported values.
Improved type handling.
Documentation for OO wrapper methods.
First support for generating methods from method-like defines.
Added more Cairo headers to test.
Automatic mapping to output files in tests.
Added CEF (Chromium Embedded Framework) to the tests and made some changes so that all files can be processed without exceptions.
Some refactorings.
Improved comment processing (///-style comments and more).
Fixed comment extraction with nested declarations.
Updated README.
ffi_lib can be nil.
When using binary layout in header.