Modify is_directory check to support symlinks to directories. This fixes #146.
Style
More minor style changes
Add --silent option to avoid any error messages.

Example:
ag --silent -m1 pattern
Merge pull request #151 from rubikitch/feature

Add --silent option to avoid any error messages.
Add link to ag.vim
Add uthash, initial symlink loop detection
Merge pull request #149 from rev112/follow_directories

Modify 'is_directory' check to fix directory symlink issue
Update README.md
Merge pull request #154 from rev112/symlinks_dir_loops

Symlink directory loop detection