Custom http log improvements (v2)

Cookie is parsed now using uint8_t pointers (iliniac PR comments) …
Changed buffer size to a power of 2 (8192) and cookie value extraction function to static (iliniac PR comments)
Added %b for request size (vinfang patch)
Writing "-" if an unknown % directive is used (vinfang patch)
Fixed bug in cookie parser
Fixed format string issue logging literal values