Added cygwin support to atom plugin

plugins/atom/atom.plugin.zsh

@@ -1,8 +1,5 @@
-# Gets OS Type
-unamestr=$(uname -s)
-
-# If OSX
-if [[ "$unamestr" == 'Darwin' ]]; then
+case $OSTYPE in
+darwin*)
     local _atom_paths > /dev/null 2>&1
     _atom_paths=(
         "$HOME/Applications/Atom.app"
@@ -15,8 +12,26 @@ if [[ "$unamestr" == 'Darwin' ]]; then
             break
         fi
     done
-# If Linux
-elif [[ "$unamestr" == 'Linux' ]]; then
+    ;;
+cygwin)
+    local _atom_path > /dev/null 2>&1
+
+    _atom_path=${LOCALAPPDATA}/atom/bin/atom
+
+    if [[ -a $_atom_path ]]; then
+        cyg_open_atom()
+        {
+            if [[ -n $1 ]]; then
+                ${_atom_path} `cygpath -w -a $1`
+            else
+                ${_atom_path}
+            fi
+        }
+
+        alias at=cyg_open_atom
+    fi
+    ;;
+linux*)
     # Alerts the user if 'atom' is not a found command.
     type atom >/dev/null 2>&1 && alias at="atom" || { echo >&2 "You have enabled the atom oh-my-zsh plugin on Linux, but atom is not a recognized command. Please make sure you have it installed before using this plugin."; }
-fi
+esac