Various updates to the pidl README file.

Remove samba3/samba4-specific comments, add comments about backends and files.

Change-Id: Id2253ce85eab7a684b2c50d25f6f2604dc146a8e
Signed-Off-By: Jelmer Vernooij <jelmer@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>

Autobuild-User(master): David Disseldorp <ddiss@samba.org>
Autobuild-Date(master): Sun Aug 31 23:47:49 CEST 2014 on sn-devel-104

pidl/README

@@ -4,7 +4,7 @@ This directory contains the source code of the pidl (Perl IDL)
 compiler for Samba 4.
 
 The main sources for pidl are available using Git as part of
-the combined Samba 3 / Samba 4 tree. Use:
+the Samba source tree. Use:
 git clone git://git.samba.org/samba.git
 
 Pidl works by building a parse tree from a .pidl file (a simple
@@ -13,10 +13,6 @@ dump of it's internal parse tree) or a .idl file
 The IDL file parser is in idl.yp (a yacc file converted to
 perl code by yapp)
 
-After a parse tree is present, pidl will call one of it's backends
-(which one depends on the options given on the command-line). Here is
-a list of current backends:
-
 Standalone installation:
 ========================
 Run Makefile.PL to generate the Makefile.
@@ -26,6 +22,10 @@ Then run "make install" (as root) to install.
 Internals overview:
 ===================
 
+After a parse tree is present, pidl will call one of it's backends
+(which one depends on the options given on the command-line). Here is
+a list of current backends:
+
 -- Generic --
 Parse::Pidl::Dump - Converts the parse tree back to an IDL file
 Parse::Pidl::Samba4::Header - Generates header file with data structures defined in IDL file
@@ -55,9 +55,10 @@ Parse::Pidl::Util - Misc utility functions used by *.pm and pidl.pl
 Parse::Pidl::Typelist - Utility functions for keeping track of known types and their representation in C
 
 Tips for hacking on pidl:
- - Look at the pidl's parse tree by using the --keep option and looking
-   at the generated .pidl file.
+ - Inspect pidl's parse tree by using the --keep option and looking at the
+   generated .pidl file.
  - The various backends have a lot in common, if you don't understand how one
-   implements something, look at the others
+   implements something, look at the others.
  - See pidl(1) and the documentation on midl
  - See 'info bison' and yapp(1) for information on the file format of idl.yp
+ - Run the tests (all in tests/)