Use RFC3986 parser

[ksss]

$ mruby -e 'p URI.parse("http://example_app.com/").to_s'

before

the scheme http does not accept registry part: example_app.com (or bad hostname?) (URI::InvalidURIError)

after

"http://example_app.com/"

[take-cheeze]

@ksss Seems like there is regexp parsing error in 00_efc3986_parser.rb.
Please try: mattn/mruby-onig-regexp#90

[ksss]

@take-cheeze Thank you for the advice.
The Onigmo did not support non-word char in group name. (ref mattn/mruby-onig-regexp#91)
I was worried about the solution, but finally I decided to change the group name in regexp.