Updates README.md with the latest VCS' segments modifications

README.md

@@ -42,19 +42,21 @@ quick look into the state of your repo:
   of commits is shown along with `⇡` or `⇣` indicating whether a git push
   or pull is pending
 
-In addition, git has a few extra symbols:
+If files are modified or in conflict, the situation is summarized with the
+following symbols:
 
-- `✎` -- a file has been modified, but not staged for commit
-- `✔` -- a file is staged for commit
+- `✎` -- a file has been modified (but not staged for commit, in git)
+- `✔` -- a file is staged for commit (git) or added for tracking
 - `✼` -- a file has conflicts
-
-FIXME
-
-- A `+` appears when untracked files are present (except for git, which uses
-  `?` instead)
+- `❓` -- a file is untracked
 
 Each of these will have a number next to it if more than one file matches.
 
+The segment can start with a symbol representing the version control system in
+use. To show that symbol, the configuration file must have a variable `vcs`
+with an option `show_symbol` set to `true` (see
+[Segment Configuration](#segment-configuration)).
+
 ## Setup
 
 This script uses ANSI color codes to display colors in a terminal. These are
@@ -215,7 +217,7 @@ settings.
 
 Some segments support additional configuration. The options for the segment are
 nested under the name of the segment itself. For example, all of the options
-for the `cwd` segment are set in `~/.powerline-shell.py` like:
+for the `cwd` segment are set in `~/.powerline-shell.json` like:
 
 ```
 {
@@ -223,13 +225,17 @@ for the `cwd` segment are set in `~/.powerline-shell.py` like:
     "cwd": {
         options go here
     }
+    "theme": "theme-name",
+    "vcs": {
+        options go here
+    }
 }
 ```
 
 The options for the `cwd` segment are:
 
-- `mode`: If "plain" then simple text will be used to show the cwd. If
-  "dironly," only the current directory will be shown. Otherwise expands the
+- `mode`: If `plain`, then simple text will be used to show the cwd. If
+  `dironly`, only the current directory will be shown. Otherwise expands the
   cwd into individual directories.
 - `max_depth`: Maximum number of directories to show in path
 - `max_dir_size`: Maximum number of characters displayed for each directory in
@@ -240,6 +246,12 @@ The `hostname` segment provides one option:
 - `colorize`: If true, the hostname will be colorized based on a hash of
   itself.
 
+The `vcs` variable has one option:
+
+- `show_symbol`: If `true`, the version control system segment will start with
+  a symbol representing the specific version control system in use in the
+  current directory.
+
 ### Contributing new types of segments
 
 The `powerline_shell/segments` directory contains python scripts which are