Instrument Pygments.start

Add an options hash to start and allow a logger to be specified by passing `:logger` through the options hash.

For example:

```ruby
#!/usr/bin/env ruby

require 'pygments'
require 'scrolls'

code = "#!/usr/bin/ruby\nputs 'foo'"

path = "/Users/asenchi/github/pygments.rb/vendor/pygments-main"
opts = {:logger => Scrolls}
Pygments.start(path, opts)
Pygments.highlight(code)
```