Expose all arguments of clang_createIndex and clang_parseTranslationUnit2

[kodemeister]

Hi @chpatrick,

This PR adds two new functions createIndexWithOptions and parseTranslationUnitWithOptions that support all arguments of libclang's clang_createIndex and clang_parseTranslationUnit2. Now you can write something like this:

let code = "int main(int argc, char **argv) { return 0; }"
idx <- createIndexWithOptions [DisplayDiagnostics]
tu <- parseTranslationUnitWithOptions idx "main.cpp" ["-Wall"] [("main.cpp", code)] [SkipFunctionBodies]

These additional options are useful to fine-tune Clang parser and process in-memory files.

I kept existing functions createIndex and parseTranslationUnit for backward compatibility but implemented them as shortcuts to createIndexWithOptions and parseTranslationUnitWithOptions.

Thanks in advance!

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This change is 

[chpatrick]

Thank you!