With support of highloadcup 2018

New params:

$ highloadcup_tester -h

  -allow-nulls
    	allow null in response data

  -diff
    	show colorful body diffs instead both variants (red - wrong, green - need)

  -utf8
    	show request & response bodies in UTF-8 human-readable format

0372de86ad6aba26d29396bd46b4b847c2b12714

20170822

update README.me