make the battery module optional for now (#234)

The 'battery' crate doesn't support Termux, so we are temporarily making the battery module optional.

src/module.rs

@@ -6,6 +6,7 @@ use std::fmt;
 
 // List of all modules
 pub const ALL_MODULES: &[&str] = &[
+    #[cfg(feature = "battery")]
     "battery",
     "character",
     "cmd_duration",

src/modules/mod.rs

@@ -1,5 +1,4 @@
 // While adding out new module add out module to src/module.rs ALL_MODULES const array also.
-mod battery;
 mod character;
 mod cmd_duration;
 mod directory;
@@ -16,6 +15,9 @@ mod ruby;
 mod rust;
 mod username;
 
+#[cfg(feature = "battery")]
+mod battery;
+
 use crate::context::Context;
 use crate::module::Module;
 
@@ -33,6 +35,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
         "git_branch" => git_branch::module(context),
         "git_status" => git_status::module(context),
         "username" => username::module(context),
+        #[cfg(feature = "battery")]
         "battery" => battery::module(context),
         "cmd_duration" => cmd_duration::module(context),
         "jobs" => jobs::module(context),

src/print.rs

@@ -26,6 +26,7 @@ const DEFAULT_PROMPT_ORDER: &[&str] = &[
     "cmd_duration",
     "line_break",
     "jobs",
+    #[cfg(feature = "battery")]
     "battery",
     "character",
 ];