fix README: add parse:true documentation
seperate usage to several blocks
fix strict_case_match bug
Merge pull request #440 from BenZhang/master

[Fix] Comparing tag names now respects strict_case_match
Merge pull request #386 from billychan/fix-readme

[Doc] README: add parse:true documentation
Improved performance with counter_cache for tags (tag.taggings_count), taken from https://github.com/lichtamberg/acts-as-taggable-on/commit/52836c54d9abf1cc77be4df7b4c61cea90869c50