minor: a few small gemfile tweaks

- removing redundant json gem in dev
- making guard notifications windows and linux friendly
reformat todo in readme
Add c extension for bson_int32?
minor: fixing copyright and license information
Merge pull request #1 from brandonblack/gemfile-fix

minor: a few small gemfile tweaks
Add extensions to gemspec
add build task to Rakefile
Add release task to Rakefile
Remove cucumber
Remove cucumber task
Remove finished refactorings
Add native machine id to object id
Add to_s to bench
Remove unused bin_data from binary
Add native float encoding
Remove bin_data note from readme
Add Float#from_bson native extension
minor: adding public and condition check to gemspec for signing
Add deserialization benchmarks
Refactor int32 read occurances