v0.2.2

Main changes:

• Improved compatibility with cdecl64;
• Huge optimization of std/matrix (now has a speed similar to numpy!);
• Adding std/stack and the std::stack structure;
• Adding std/json (experimental version - only parser, without error handling) and example for it;

Minor changes:

• New function std::cstring::stod (string to double), new method std::string.toDouble();
• New methods std::file.readAll() and std::file.u8ReadAll().