Support align and min_width module options

This patch enables users to define "align" and "min_width" options
right in the i3status module config sections.

Specifically this patch:
 * Adds macros for the two new options that are used in the option
   definitions. As the min_width option can take either a string or a
   number, a custom type has been added along with a corresponding callback
   function that parses the provided value (and provides input validation).
   The align option also uses a callback for input validation
 * Expands all module config option definitions to include the new
   options
 * Extends the SEC_CLOSE_MAP() macro to generate the JSON for the new
   options as necessary
 * Updates the manpage to explain the new options

1 files changed, 29 insertions, 0 deletions

diff --git a/man/i3status.man b/man/i3status.man
index 7ba4422..656a8bf 100644
--- a/man/i3status.man
+++ b/man/i3status.man
@@ -404,6 +404,35 @@ volume master {
 }
 -------------------------------------------------------------
 
+== Universal module options
+
+When using the i3bar output format, there are a few additional options that
+can be used with all modules to customize their appearance:
+
+align::
+	The alignment policy to use when the minimum width (see below) is not
+	reached. Either +center+ (default), +right+ or +left+.
+min_width::
+	The minimum width (in pixels) the module should occupy. If the module takes
+	less space than the specified size, the block will be padded to the left
+	and/or the right side, according to the defined alignment policy. This is
+	useful when you want to prevent the whole status line from shifting when
+	values take more or less space between each iteration.
+	The option can also be a string. In this case, the width of the given text
+	determines the minimum width of the block. This is useful when you want to
+	set a sensible minimum width regardless of which font you are using, and at
+	what particular size. Please note that a number enclosed with quotes will
+	still be treated as a number.
+
+*Example configuration*:
+-------------------------------------------------------------
+disk "/" {
+    format = "%avail"
+    align = "left"
+    min_width = 100
+}
+-------------------------------------------------------------
+
 == Using i3status with dzen2
 
 After installing dzen2, you can directly use it with i3status. Just ensure that