alpha 0.3

• Update README and highlight theme
• Add os_name, os_release and os_version constants (read the Wiki for more info)
• extend builtin function can now delete duplicates (read the Wiki for more info)
• first argument of print and print_ret builtin functions is no longer required (e.g. print() is like print('')
• Add special *[...] syntax. More infos in the Wiki, in functions and lists.
• Better error messages
• Bugfixes