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/README.md

@@ -0,0 +1,15 @@
+# GDPM HTTP Example
+
+This is an example showing how to use the GDPM HTTP library to download files. The library uses RapidJSON to get results.
+
+
+Here is a quick snippet to get started:
+```c++
+// Get a full list of assets
+rest_api::context context = rest_api::make_context();
+rapidjson::Document doc = http::get_asset_list(
+	"https://godotengine.org/asset-library/api",
+	context
+)
+// ... parse the rapidjson::Document
+```

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;
+}

examples/rest_api/README.md

@@ -0,0 +1,26 @@
+# GDPM Rest API Example
+
+This is an example showing how to use the REST API designed to query the Godot Asset library in C++. It is built using the `libcurl` library.
+
+Here is a snippet making a HTTP get and post request.
+
+```c++
+using string 	= std::string;
+using headers_t = std::unordered_map<string, string>;
+
+std::string url = "www.example.com";
+http::response r_get = http::request_get(url)
+if(r_get.response_code == http::response_code::OK){
+	// ...do something...
+}
+
+http::request_params params;
+params.headers = {
+	{"user-agent", "firefox"},
+	{"content-type", "application/json"}
+}
+http::response r_post = http::request_post(url, params);
+if(r_post.response_code == http::response_code::OK){
+	// ...do something...
+}
+```

examples/rest_api/main.cpp

@@ -0,0 +1,8 @@
+/*! Example using the `libgdpm-restapi` library */
+
+#include "rest_api.hpp"
+
+
+int main(int argc, char **argv){
+	return 0;
+}