implement string

[proppy]

[lpereira]

Strings can be quite tricky on a microcontroller. std::string is quite heavyweight, even with small string optimization tricks (which aren't much of a gain when your size_t and void* have their sizeof() == 2).

Arduino has its own String object which is quite okay for a first step in having strings implemented. However, if at all possible, I'd like to keep mugo slightly more agnostic in terms of supported platforms.

Another thing to consider is that on AVR microcontrollers, there's PROGMEM, which can greatly reduce the amount of memory required for a sketch; it would be nice to support that automatically eventually.