Change full_options to pre-process LazyHighCharts options

Now recognizes when JS code is being included as a JSON value
and is correctly pre-processed (as in the high_charts HTML helper)
Change file loading order
Remove ruby-head from travis
Merge pull request #4 from singjsong/feature/formatter-bugfix

Change full_options to pre-process LazyHighCharts options
Return chart Tempfile, option for other image formats
Render refactoring, accompanying spec
Comment change
Merge pull request #5 from singjsong/feature/formatter-bugfix

Return chart Tempfile, option for other image formats
Merge branch 'feature/formatter-bugfix' into develop
Merge branch 'develop' of https://github.com/market76/lazy_high_charts into develop