Bugfix/encoding

remove detect_enoding. detect_encoding means force_encoding to the file.data's encoding, not encoding to utf8. will cause encoding problem.

Refactoring and assets cleanup

[ci skip]

[ci skip]

Travis and Ruby 1.9.3

Conflicts:
	lib/gitlab/encode.rb

This helps fix cases where UTF-8 is wrongly identified as ISO-8859-1. We will only try to convert strings if we are 100% sure about the charset, otherwise, we will fallback to UTF-8.

It's dangerous to rescue errors here as it will hide bugs. define_tree_vars already catch all situations where something may not exist.

Updated; libreadline-dev > libreadline-gplv2-dev

;) Have fun!