dot style paths fail if the key has a colon in the name

[mmorga]

I've submitted a PR #41 with a fix for this (and accompanying test).

[Skarlso]

Hey @mmorga. This gem is no longer maintained. Care to pop over to https://github.com/Skarlso/jsonpathv2 and submit your PR there? :)

[Skarlso]

Applied to issue to the refactorings.