list: add list_add_tail()
parser: initial parse_script()
parser: add many structural changes to script, function, block and instruction
vec: initial commit
vec: add simple initializer
parser: use vec API
vec: remove debugs
parser: fix parsing of function arguments
main: parse script from stdin
parse: use vec in to parse_function()
list: use safe variant for iterator
parse: add destroy_script() function
parse: add script dumping
parse: add parsing and dumping of nested blocks and colons
test: script: add 2 basic tests
parse: fix error handling
parse: rename *_inst_block to *_block
parser: add basis for expression parsing
parse: add stup for destroy_expr()
parse: fix memleak in parse_block()