Make indent size configurable

[leebrooks0]

It would be nice if indent size (set here https://github.com/CraigWilliams/BeautifyRuby/blob/master/lib/rbeautify/config/ruby.rb#L10)
were configurable in the settings file, personally I would like 4 spaces even though it is against the grain of 2 spaces.

[sfengyuan]

Only one space for me ,don't why

[kevinchugh]

Looks like you just merged a PR for this, how do we use it? thanks for any info.

[CraigWilliams]

@kevinchugh Setting the "tab_size" in Preferences.sublime-settings