Replacing &blck.call with yield

Based on performance tests from lotus/view#33, replacing block.call
with yield

I have modified the documentation to include the @yield and
@yieldparam from the Yardoc tags (see below):

http://rubydoc.info/gems/yard/file/docs/Tags.md#yield
Added test for Utils::Hash serialization for a nested hash
Expanded test for Utils::Hash #to_h
Utils::Hash#to_h return instances of ::Hash in case of nested symbolized data structure
Moved JRuby to the allowed failures for CI

See:

  https://github.com/jruby/jruby/issues/2053
Test CI against Ruby 2.2.0-preview1
Merge pull request #31 from jeremyf/replacing-amp-block-with-yield

Replacing &blck.call with yield
Added more tests for Utils::String#underscore. Closes #32
Improved error NameError message by passing in the whole constant name
Merge branch 'tomkadwill-improved_name_error_message'
Improved error message for Utils::Class.load! Ref #33
new underscore implementation

remove benchmarking code
Merge branch 'KillaPL-string_underscore_optimisation'
Use 1/3 less objects when using Lotus::Utils::Kernel.Array

See: https://gist.github.com/jodosha/c034ac73939aa4c769db
Merge pull request #36 from lotus/faster-kernel-array

Faster and less memory intensive Utils::Kernel.Array
updated CHANGELOG for v0.3.0 release
Merge pull request #37 from bennyklotz/master

Updated CHANGELOG for v0.3.0 release
[ci skip] Update API doc with 0.3.0
Prepare for v0.3.0
[ci skip] API doc adjustments