fix: compile errors on windows

calendar.rs had some left over icon! macro_rules macros referencing now
deleted files.

bundle::get was defined twice on non-unix platforms.

A known remaining issue is that projects using libcosmic need to have
cosmic-icons in their project root, since the crabtime macro uses
crabtime::WORKSPACE_PATH rather than the path to wherever cargo puts
libcosmic's git submodule.

See: 639326fcc3

src/widget/icon/bundle.rs

@@ -4,6 +4,7 @@
 //! Embedded icons for platforms which do not support icon themes yet.
 
 /// Icon bundling is not enabled on unix platforms.
+#[cfg(unix)]
 pub fn get(icon_name: &str) -> Option<super::Data> {
     None
 }