Add configure options for zlib and lzma support

Without configure options the support is automagic so it can't be easily
disabled if the required libraries exist on the build machine.
Merge pull request #345 from radhermit/automagic

Add configure options for zlib and lzma support
Print correct line numbers when searching streams.
Update README.md

FreeBSD's `pkg_add` needs `-r` to fetch remote packages.
Tag release 0.20.0.
It's 2014
skip FIFO mode check if stdin doesn't exist

The creating pipe can make pipe no stdin, so I support no stdin.
fix condition
Update copyright to a date range. Apparently that's what it's supposed to be.
Declare these targets as phony. That way you can make test all day long.
Run ag closer to normal mode in testing.
Add test for ignoring subdirectories.
Braces.
Fix tiny memory leak. Only strlen(base_path) once. Make patterns that start with ./ behave just like those that start with /.
Merge pull request #351 from byplayer/support_no_stdin

skip FIFO mode check if stdin doesn't exist
Slightly better test name. There will be more tests for ignores.
ZERO AND ZERO IS ZERO
TODO
Don't call filename_ignore_search twice with the same filename.
Meh. Don't use strcmp.