Revert "fish has renamed . to source"

As @GlitchMr commented, fish 2.1 has not been released yet and even
then, the command . will only be deprecated, not removed.

This reverts commit 03833fda7b.

oh-my-fish.fish

@@ -33,11 +33,11 @@ function _fish_source_plugin_load_file
   set -l load_file_path "plugins/$plugin/$plugin.load"
 
   if test -e $fish_path/$load_file_path
-    source $fish_path/$load_file_path
+    . $fish_path/$load_file_path
   end
 
   if test -e $fish_custom/$load_file_path
-    source $fish_custom/$load_file_path
+    . $fish_custom/$load_file_path
   end
 end
 
@@ -80,7 +80,7 @@ _fish_load_theme $fish_theme
 
 # Source all files inside custom folder
 for config_file in $fish_custom/*.load
-  source $config_file
+  . $config_file
 end
 
 # Re-adding user's functions so they have the highest priority

plugins/fry/fry.load

@@ -1,4 +1,4 @@
 ### Main program
 if test -d /usr/local/share/fry/fry.fish
-  source /usr/local/share/fry/fry.fish
+  . /usr/local/share/fry/fry.fish
 end

templates/config.fish

@@ -12,4 +12,4 @@ set fish_theme robbyrussell
 #set fish_custom $HOME/dotfiles/oh-my-fish
 
 # Load oh-my-fish configuration.
-source $fish_path/oh-my-fish.fish
+. $fish_path/oh-my-fish.fish