Minor bug fixes and improvements

- Update `README.md` file with minor changes
- Added `max_results` parameter to config for persistence
- Added `csv2`, `tabulate`, and `indicators` as included dependencies
- Added downloading progress bar that *sometimes* work
-Added HTTP request header handling with curl
- Added more options to some commands
- Moved `http` functions into `context` class

TODO: Fix optional parameters not working correctly
NOTE: Github does not always return `Content-length` HTTP response header

include/config.hpp

@@ -27,6 +27,7 @@ namespace gdpm::config{
 		string_map remote_sources;
 		size_t jobs					= 1;
 		size_t timeout				= 3000;
+		size_t max_results			= 200;
 		bool enable_sync			= true;
 		bool enable_cache			= true;
 		bool skip_prompt			= false;