When adding minified files for review the entire file is displayed in 

the diff veiwer. Since min files are just one long line this does not

make sense to display as they are generally ignored in the review

process. With this change files matching the search .min. are hidden

by default with the option to display them if the reviewer clicks 

"Show content". This is similar to how deleted files are handled in the

diff viewer. Since deleted and hidden files are very similar in 

functionality I merged the fields into one hidden field with an 

optional hidden_context if there is need to know the reason for a file

being hidden.

Included tests for these changes.