Experimental C extension
Rake compile+spec as default
Added vanitygen files
Added library dependencies
Renamed vanitygen_cext to make C maintenance easier
Vanitygen.difficulty in C
Autoloading
Rudimentary support for generating keys. Fugly!
Convert strings to symbols
Really simple integration
Removed runtime dependency on bitcoin-ruby
Using wallet import format over private_key
Minor code tweaks
Renamed Cext to Ext.  Cext looks really weird
Reference C files via submodule
Split up into many files
Check types in C land
Merge branch 'c'