More refactoring and bug fixes

- Added `libhttp` and `librest_api` targets to CMakeLists.txt
- Added examples for `libhttp` and `librest_api` in examples directory
- Added `cache` and `add` commands
- Added documentation for `libhttp` and `librest_api`
- Added all available HTTP response codes to REST API
- Changed how `bin/compile.sh` works (must supply args to build)

examples/http/main.cpp

@@ -0,0 +1,9 @@
+/*! Example using the `libgdpm-http` library
+*/
+
+#include "http.hpp"
+
+
+int main(int argc, char **argv){
+	return 0;
+}