hledger's built-in commands.

Each command has a similarly-named module, Somecommand.hs.

Each command's help is kept in Somecommand.md. 
This file is included by Somecommand.hs to help build the command's --help output,
and by hledger/hledger_commands.m4.md to help build the hledger manual.
It has some special features:

- The first line should specify the command name and any aliases,
  as space or comma-separated words.

- A line containing just _FLAGS_ will be replaced in --help output by
  the command's flags list. Lines above _FLAGS_ are known as the short help.
  If there's no such line, the flags will be displayed at the end. 
  In the manual, no flags list is shown.

- Markdown can be used to influence the appearance of the manuals,
  especially the html version. But the markup will also appear
  uninterpreted in the --help output, so use sparingly.

- Use only one newline on the first line (or cmdargs will display the
  short help with two newlines after each line). This also means
  cmdargs will strip out any blank lines, which prevents use of some
  markdown features.

- Keep the width of short help lines to 76 characters or less, or
  cmdargs will insert newlines.

- GHC, stack, cabal, ghcid etc. won't notice changes in this file;
  you have to also touch the .hs file.
