v2.1

New version, though a pretty small update. Here's the new stuff in v2.1.

• Added repeat command (evaluates a floor expression and uses it as a counter)
• Added sgn as a new expr math function/operator
• Fixed a buffer bug which could have led to UB
• Better arrays:
  • Added arr <a> (returns key/value pairs)
  • Added arr <a> keys (returns keys)
  • Added arr <a> vals (return values)
  • Array keys are now sorted by numeric value (if possible), or by string index otherwise

Have fun! ;)