gem build warnings

[itspriddle]

These warnings appear when you build the gem. They aren't causing any issues, but we should refactor the gemspec to eliminate them:

gem build lumberg.gemspec

WARNING:  no homepage specified
WARNING:  open-ended dependency on json (>= 1.8.2) is not recommended
  if json is semantically versioned, use:
    add_runtime_dependency 'json', '~> 1.8', '>= 1.8.2'
WARNING:  pessimistic dependency on faraday (~> 0.9.0) may be overly strict
  if faraday is semantically versioned, use:
    add_runtime_dependency 'faraday', '~> 0.9', '>= 0.9.0'
WARNING:  pessimistic dependency on faraday_middleware (~> 0.9.0) may be overly strict
  if faraday_middleware is semantically versioned, use:
    add_runtime_dependency 'faraday_middleware', '~> 0.9', '>= 0.9.0'
WARNING:  pessimistic dependency on rspec (~> 2.10.0, development) may be overly strict
  if rspec is semantically versioned, use:
    add_development_dependency 'rspec', '~> 2.10', '>= 2.10.0'
WARNING:  pessimistic dependency on webmock (~> 1.18.0, development) may be overly strict
  if webmock is semantically versioned, use:
    add_development_dependency 'webmock', '~> 1.18', '>= 1.18.0'
WARNING:  pessimistic dependency on vcr (~> 2.9.2, development) may be overly strict
  if vcr is semantically versioned, use:
    add_development_dependency 'vcr', '~> 2.9', '>= 2.9.2'
WARNING:  pessimistic dependency on rake (~> 0.9.2.2, development) may be overly strict
  if rake is semantically versioned, use:
    add_development_dependency 'rake', '~> 0.9', '>= 0.9.2.2'
WARNING:  See http://guides.rubygems.org/specification-reference/ for help