Merge pull request #33 from sustr4/specupdate

Merging another batch of spec updates, still WIP

* Introduces some non-critical issues which will be fixed in a subsequent pull request
Moved devel deps to Gemfile

It's not ideal but it will allow us to specify platform-specific
devel dependencies without breaking compatibility.
Merge pull request #34 from arax/dep_fixes

Moved devel deps to Gemfile
An attempt to fix Entity#check

Now, it should be possible to mix initialized attributes with
defaults or uninitialized attributes and run a successful #check
on them. There is no need to use #convert.
Merge pull request #35 from arax/attr_check_fix

An attempt to fix Entity#check