Update everything

I originally wanted to add a way to set flags but got carried away:

* Update V8 to 3.27.5 (about a week old)
* Add i18n support (will add v8/initialize-icu and test cases)
* Add ability to set flags e.g. --harmony (v8/set-flags, will add test cases)
* Update JNA to 4.1.0
* Set Clojure dependency to 1.6.0, remove Midje
* Remove jvm-opts (would find x86 before x86-64 and fail)
* Remove .clj-v8 suffix, extract to clj-v8 temporary directory instead
* Use `patchelf` to set rpath to '.:$ORIGIN' uniformly (so that e.g. libv8 can be loaded on its own)
* Bump version numbers: clj-v8 0.1.6 and clj-v8-native 0.1.5

Passes test cases and 'check' target; will add a few more for new things. Also need to check uberjar support (should still work but need to verify).