Ignore Exceptions during rule set and list render

if output format has `setIgnoreExceptions(true)` or `beLenient()`

Update CHANGELOG for 5.2

Update README.md

Add HHVM tested seal of approval

Update CHANGELOG.md to reflect changes since 5.0.4

Better lenient parsing tests

Merge remote-tracking branch 'vladkens/feature'

* vladkens/feature:
  Uses multibyte string only if loaded mbstring extension.

Update readme to show simpler phpunit invocation

Add missing test file

Used for testEndToken in LenientParsingTest

Closes MyIntervals#64 as fixed

Don’t use print_r

It sometimes conflicts with output buffering

Merge remote-tracking branch 'slusarz/float_fix'

* slusarz/float_fix:
  Fix Size output for locales that use non-period decimal separators

Closes MyIntervals#61 as fixed