Add std.textmacro module

[dlangBugzillaToGithub]

bugzilla (@WalterBright) reported this on 2013-01-08T17:41:38Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=9282

CC List

• hsteoh
• lt.infiltrator

Description

The ddoc text macro system in the dmd source code macro.h and macro.c should be implemented as a phobos module.

The inputs should be:

1. an input range

2. an associative array of key=value pairs for the macro definitions

And the output should be another input range for the expanded output.