Support 2.4/2.5 rubies

[razum2um]

After this the gem should properly work on ruby 1.9-2.5 inclusively, without warnings 🎉

What's addressed inside:

• warnings/missing Fixnum/Bignum/Data
• new FrozenError
• fixes related updated bundler, webrick, ox

What I'm concerned about (maybe we'd better change test logic)

• some workarounds for a ruby bug with line numbers and new did-you-mean enabled by default
• I had to change openssl verify_depth to 0 since with 1 the insufficient cert chain doesn't raise (both travis & locally the same) - if you understand this, please, tell me what you think :)

Also handled some things discussed in #8 which should make further testing more predictable

• time-dependent specs are executed with stubbed time
• errors caused by "port is used" are auto retried now

What's totally broken after this:

• ruby-1.8
• anything with libxmlparser

Sorry for a big PR, feel free to take some commits apart and comment on.

[rubyjedi]

Thanks for the PR!

Looks good; I've no problem with libxmlparser being broken for the time being - I don't think that's really in demand these days with the more modern parsers available as options. 'Would like to get that working again for completeness' sake, but that can be a battle for another day.

Merging. Again, thanks for all the time and effort put into forward-porting to Ruby 2.4 and 2.5

[razum2um]

@rubyjedi thanks 👍 could you also release to rubygems?

[razum2um]

@rubyjedi thanks, sorry for a necroreply, but I saw you pulished soap4r-ng-2.0.4, but could you bump rubyjedi-soap4r since it has almost twice more downloads (more dependent packages I think) but the code inside is the same, just not to change all 3rd party deps and just update the transitive (rubyjedi-soap4r) one?