bobthefish: allow user disable segments

Conflicts:
	themes/bobthefish/fish_prompt.fish

fish_prompt.fish

@@ -12,9 +12,16 @@
 #
 # You can override some default options in your config.fish:
 #
+#     set -g theme_display_git no
+#     set -g theme_display_hg no
+#     set -g theme_display_virtualenv no
 #     set -g theme_display_user yes
 #     set -g default_user your_normal_user
 
+set -q theme_display_git; or set -g theme_display_git yes
+set -q theme_display_hg; or set -g theme_display_hg yes
+set -q theme_display_virtualenv; or set -g theme_display_virtualenv yes
+
 set -g __bobthefish_current_bg NONE
 
 # Powerline glyphs
@@ -95,10 +102,12 @@ function __bobthefish_pretty_parent -d 'Print a parent directory, shortened to f
 end
 
 function __bobthefish_git_project_dir -d 'Print the current git project base directory'
+  [ "$theme_display_git" = 'yes' ]; or return
   command git rev-parse --show-toplevel ^/dev/null
 end
 
 function __bobthefish_hg_project_dir -d 'Print the current hg project base directory'
+  [ "$theme_display_hg" = 'yes' ]; or return
   set d (pwd)
   while not [ $d = / ]
     if test -e $d/.hg
@@ -331,6 +340,7 @@ function __bobthefish_virtualenv_python_version -d 'Get current python version'
 end
 
 function __bobthefish_prompt_virtualfish -d "Display activated virtual environment (only for virtualfish, virtualenv's activate.fish changes prompt by itself)"
+  [ "$theme_display_virtualenv" = 'yes' ]; or return
   set -q VIRTUAL_ENV; or return
   set -l version_glyph (__bobthefish_virtualenv_python_version)
   if [ "$version_glyph" ]