libripgrep: initial commit introducing libripgrep

libripgrep is not any one library, but rather, a collection of libraries
that roughly separate the following key distinct phases in a grep
implementation:

  1. Pattern matching (e.g., by a regex engine).
  2. Searching a file using a pattern matcher.
  3. Printing results.

Ultimately, both (1) and (3) are defined by de-coupled interfaces, of
which there may be multiple implementations. Namely, (1) is satisfied by
the `Matcher` trait in the `grep-matcher` crate and (3) is satisfied by
the `Sink` trait in the `grep2` crate. The searcher (2) ties everything
together and finds results using a matcher and reports those results
using a `Sink` implementation.

Closes #162

grep2/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "grep2"
+version = "0.2.0"  #:version
+authors = ["Andrew Gallant <jamslam@gmail.com>"]
+description = """
+Fast line oriented regex searching as a library.
+"""
+documentation = "http://burntsushi.net/rustdoc/grep/"
+homepage = "https://github.com/BurntSushi/ripgrep"
+repository = "https://github.com/BurntSushi/ripgrep"
+readme = "README.md"
+keywords = ["regex", "grep", "egrep", "search", "pattern"]
+license = "Unlicense/MIT"
+
+[dependencies]
+grep-matcher = { version = "0.0.1", path = "../grep-matcher" }
+grep-printer = { version = "0.0.1", path = "../grep-printer" }
+grep-regex = { version = "0.0.1", path = "../grep-regex" }
+grep-searcher = { version = "0.0.1", path = "../grep-searcher" }
+
+[features]
+avx-accel = ["grep-searcher/avx-accel"]
+simd-accel = ["grep-searcher/simd-accel"]