replace grit with rugged

  Removed features: graphs, repository download
update ruby hash syntax
add ruby 2.0 to travis-ci
update rouge dependency
remove redundant script
remove grit references
fix sorting branches by name
fix commit diff
add repository navigation
use unobtrusive warning for empty repo description
fix diff highlighting
show repo navigation only for branch
don't highlight source for binary files
find commit by tag name
fix broken spec
improve specs
import necessary code from git-webby
initial implementation of repository license detection
refactor license detection
add more specs