Reconstruct with isahc and async-std

`isahc` uses libcurl as backend which handles complicated HTTP protocol.

The old codes have many messy construction.  At this commit, we rewrite
all codes and let them have independent relationship as much as possibe.

Now, aget-rs supports to asynchronically download http/s content and
m3u8 stream videos.

.gitignore

@@ -1 +1,2 @@
 /target
+Cargo.lock

.travis.yml

@@ -4,14 +4,19 @@ dist: xenial
 
 matrix:
   include:
-    # Stable channel.
+    # Build on linux
     - os: linux
-      rust: stable
-      env: TARGET=x86_64-unknown-linux-gnu
+      rust: nightly
+      env:
+        - TARGET=x86_64-unknown-linux-gnu
+        - DEPLOY=true
 
+    # Build on osx
     - os: osx
-      rust: stable
-      env: TARGET=x86_64-apple-darwin
+      rust: nightly
+      env:
+        - TARGET=x86_64-apple-darwin
+        - DEPLOY=true
 
     # Code formatting check
     - os: linux
@@ -21,8 +26,9 @@ matrix:
         - cargo install --debug --force rustfmt-nightly
       script: cargo fmt -- --check
 
+    # Test benchmark
     - os: linux
-      rust: stable
+      rust: nightly
       install: cargo build
       script: bash ci/benchmark.bash
 
@@ -75,7 +81,7 @@ deploy:
     # deploy only if we push a tag
     tags: true
     # deploy only on stable channel that has TARGET env variable sets
-    condition: $TRAVIS_RUST_VERSION = stable && $TARGET != ""
+    condition: $DEPLOY = true && $TARGET != ""
 
 notifications:
   email:

Cargo.toml

@@ -19,19 +19,18 @@ edition = "2018"
 name = "ag"
 path = "src/main.rs"
 
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
 [dependencies]
-percent-encoding = "2.1"
-term_size = "0.3"
-ansi_term = "0.12"
 bytes = "0.5"
-failure = "0.1"
-
+isahc = { version = "0.9", features = ["cookies"] }
 futures = "0.3"
-futures-util = "0.3"
-actix-rt = "1.0"
-awc = { version = "1.0", features = ["openssl"] }
-
-[dependencies.clap]
-version = "2.33"
-default-features = false
-features = [ "suggestions", "color" ]
+async-std = { version = "1", features = ["unstable"] }
+thiserror = "1.0"
+term_size = "0.3"
+ansi_term = "0.12"
+openssl = "0.10"
+clap = "2"
+percent-encoding = "2"
+m3u8-rs = "1"
+url = "2"