Helper extensions

Extension methods on strings, lists and dictionaries.

Type	What it does
StringExtensions	Hex ↔ number (with gwei/eth scaling), Base64, flattening JSON, account ranges, Telegram Markdown escaping, JWT decoding, passwords.
ListExtensions	`Rnd`: a random item, optionally removed.
ProjectExtensions (MethodExtensions)	ZennoPoster lists ↔ `List<string>` (`ListSync`, `RndFromList`, `ListFromFile`), `DicToVars`, `ToJson`.

string wei = "0.01".StringToHex("eth");          // 0x2386F26FC10000
string next = project.RndFromList("proxies", remove: true);