Make skeptic an optional build dependency

Cargo.toml

@@ -11,8 +11,9 @@ readme = "Readme.md"
 repository = "https://github.com/gyscos/Cursive"
 version = "0.3.2"
 
-[build-dependencies]
-skeptic = "0.6"
+[build-dependencies.skeptic]
+optional = true
+version = "0.6"
 
 [dependencies]
 odds = "0.2"
@@ -20,23 +21,23 @@ toml = "0.2"
 unicode-segmentation = "0.1"
 unicode-width = "0.1"
 
+[dependencies.bear-lib-terminal]
+optional = true
+version = "1.3.1"
+
 [dependencies.ncurses]
-version = "5.83.0"
 features = ["wide"]
 optional = true
+version = "5.83.0"
 
 [dependencies.pancurses]
-version = "0.6"
 features = ["wide"]
 optional = true
+version = "0.6"
 
 [dependencies.termion]
+optional = true
 version = "1.1.1"
-optional = true
-
-[dependencies.bear-lib-terminal]
-version = "1.3.1"
-optional = true
 
 [dev-dependencies]
 rand = "0.3"

build.rs

@@ -1,8 +1,12 @@
-extern crate skeptic;
-
+#[cfg(skeptic)]
 fn main() {
+    extern crate skeptic;
+
     skeptic::generate_doc_tests(&["Readme.md",
                                   "doc/tutorial_1.md",
                                   "doc/tutorial_2.md",
                                   "doc/tutorial_3.md" ]);
 }
+
+#[cfg(not(skeptic))]
+fn main() {}