Use docopt for argument parsing

This commit switches bindgen over to using the docopt crate for argument parsing
instead of manual argument parsing. This required two notable changes in the
arguments and flags style:

1. All flags of the form `-foo` are now of the form `--foo`.

2. We can no longer pass unknown flags straight through to clang. Instead, the
user appends `--` after the bindgen flags and input header, after which point
any more flags and arguments get collected and passed to clang. This required
changes to the test runner and the `// bindgen-flags` comments.

Author: fitzgen

Cargo.toml

@@ -1,38 +1,49 @@
 [package]
-name = "bindgen"
-version = "0.16.0"
-description = "A binding generator for Rust"
 authors = ["Jyun-Yan You <[email protected]>"]
-license = "BSD-3-Clause"
+build = "build.rs"
+description = "A binding generator for Rust"
 homepage = "https://github.com/crabtw/rust-bindgen"
-repository = "https://github.com/crabtw/rust-bindgen"
+keywords = ["bindings", "ffi", "code-generation"]
+license = "BSD-3-Clause"
+name = "bindgen"
 readme = "README.md"
-keywords = [ "bindings", "ffi", "code-generation" ]
-build = "build.rs"
+repository = "https://github.com/crabtw/rust-bindgen"
+version = "0.16.0"
 
-[dependencies]
-aster = { version = "0.21.1", features = ["with-syntex"] }
-quasi = { version = "0.15", features = ["with-syntex"] }
-clippy = { version = "*", optional = true }
-syntex_syntax = "0.38"
-log = "0.3.*"
-libc = "0.2.*"
-clang-sys = "0.8.0"
+[[bin]]
+doc = false
+name = "bindgen"
 
 [build-dependencies]
 quasi_codegen = "0.15"
 
+[dependencies]
+clang-sys = "0.8.0"
+docopt = "0.6.82"
+libc = "0.2.*"
+log = "0.3.*"
+rustc-serialize = "0.3.19"
+syntex_syntax = "0.38"
+
+[dependencies.aster]
+features = ["with-syntex"]
+version = "0.21.1"
+
+[dependencies.clippy]
+optional = true
+version = "*"
+
+[dependencies.quasi]
+features = ["with-syntex"]
+version = "0.15"
+
 [features]
-static = []
 llvm_stable = []
+static = []
 
 [lib]
 name = "bindgen"
 path = "src/lib.rs"
 
-[[bin]]
-name = "bindgen"
-doc = false
-
 [[test]]
 name = "tests"