Add Debian and Ubuntu install instructions
Merge pull request #246 from mizuno-as/master

Add Debian and Ubuntu install instructions
Add support for search-by-language.

(List of language files from whatever version of Ack I had laying around)
remove language list duplication
doco for search-by-language
fix #217
Skip long lines (fixes #189)
Major refactor of ignore code.  Fixes #168.  Fixes #127.
fix handling of hgignore files (refs #127)
completions for languages and long-line-length
fix #208
do many fewer filename matches
process ignores in reverse order
correct order of comparisons to prevent walking off end of array
fix fencepost error
study patterns for ignores
fix uninitialized var
use alternations for regexes (speedup)
Add support for .bzrignore
Add an initial implementation of the shortoutput option

Add a description and configuration option for --[no]shortoutout for
shorter match output; add an initial whitespace standardisation
implementation