v2.5

New update with a bunch of features added!

• Added .= to set for string concatenation;
• Added caller command, for Bash style stack traces;
• Added try/catch and throw;
• Added logical (non-bitwise) ^^ XOR operator in expr;
• > actually opens files in O_TRUNC now (rookie mistake);
• fn prompt no longer forces its output to stderr, user can choose where his prompt goes now;
• FD management no longer does manual counting, uses fcntl instead;
• More RAII in the codebase, reducing bugs.