This commit will hopefully allow the cimport method to be used just as one
would use #inclue <header.h> in C. It follows the following method:
1. create a pseudoheader file that #include's all the requested header files
2. runs the pseudoheader through the C preprocessor (it will try various
compilers if available on the system).
3. runs the preprocessed file through a C formatter, which attempts to group
statements on one line. For example, a struct definition that was
formerly on several lines will take just one line after formatting. This
is done so that unique declarations can be detected. Duplicates are thus
easy to remove.
4. remove lines that are too complex for the LuaJIT C parser (such as:
Objective-C block syntax, crazy enums defined on linux, ...)
5. remove duplicate declarations
6. pass result to ffi.cdef
