Fix #98

`irony--libclang-lang-compile-options' should be called out of `with-temp-buffer'.
Merge pull request #121 from tsukimizake/master

irony-pp: call `irony--libclang-lang-compile-options' out of `with-temp-buffer' (fix #98)
Completion: avoid use of defsubst in public API

It may be better to avoid uses of defsubst in the public API as it may
lead to unexpected results (when company-irony is compiled without
irony-mode?), see:

https://github.com/Sarcasm/irony-mode/issues/83#issuecomment-50287917