Upgrade to H3 v4 (#49)

* Switch to h3 and h3-js 4.1.0 and basic find-and-replace of function names (not handling H3Error correctly yet)

* It compiles now, but some tests don't work

* Fix all but one test. That one's a bit puzzling

* All tests passing, adding another TODO

* 1, 2, 5!

* Memory safety

.prebuild.sh

@@ -7,7 +7,7 @@ COMMON_CMAKE_ARGS=-DCMAKE_BUILD_TYPE=Release
 npm run clean &&
   git clone https://github.com/uber/h3 &&
   cd h3 &&
-  git checkout v3.7.2 &&
+  git checkout v4.1.0 &&
   if command -v make; then
     if [[ "${ARCH}" == "ia32" ]]; then
       cmake . ${COMMON_CMAKE_ARGS} -DCMAKE_C_FLAGS="-fPIC -m32";

binding.gyp

@@ -1,7 +1,8 @@
 {
   "targets": [{
     "cflags": [
-      "-std=c99"
+      "-std=c99",
+      "-Wno-empty-body"
     ],
     "target_name": "h3node",
     "include_dirs": [