Set PCRE backtrack limit only in PCRE tests
Add docs for PcreRegex::grep, flags param and tests
Add docs for PcreRegex::filter, limit param and tests
Support better extensibility by using late static binding and protected methods
Move pattern formatting to  RegexException
Add PcreRegexException test
Remove composer.lock
Update composer.json with description, keywords and requires
Updated README to be up to date to code

Added
- short description
- Installation
- Why should I care? / What problem does it solve?
- Usage / Here comes the solution
- Unified API
- Requirements
- Note on HHVM
- FAQ
- Contribute