Merge pull request #8 from maedama/master

fixed Keyword::Draft4::Enum to match to JSON::null
moved t/lib => lib
removed use t/lib
updated cpanfile
Merge pull request #9 from maedama/feature/perl-jsv

Feature/perl jsv
context
log_error
pass all tests
hmmm
process history
inline-able method
remove use JSV::Exception
throw immediate
remove pointer_tokens
error retrieval with JSON pointer
Merge pull request #14 from zigorou/context

Context始めました
expaned retval
Merge pull request #15 from zigorou/retval

expaned retval
hmmm...
need test...