provide config for editorconfig plugins

* If a dev adds an editorconfig plugin to their editor,
  automatically configure their editor for code style.

* Specify 4-space softtabs so new code will be compatible
  with Python 3.

* Put the same settings in .gitattributes so git diff
  highlights whitespace errors.

.editorconfig

@@ -0,0 +1,23 @@
+; Unify the coding style for different editors and IDEs.
+; Plugins are available for emacs, vim, gedit, textmate, and more
+; at http://editorconfig.org/#download
+;
+; See http://editorconfig.org or https://github.com/editorconfig/
+;
+; If you change a setting in this file,
+; you should also change .gitattributes
+
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.py]
+indent_size = 4
+
+[*.yml]
+indent_size = 2

.gitattributes

@@ -0,0 +1,14 @@
+######################################################################
+# gitattributes(5) describes the format and usage of this file.
+#
+# https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html
+# http://git-scm.com/book/ch7-2.html
+# http://urbanautomaton.com/blog/2011/07/28/git-grep-and-language-specific-diffs/
+# https://help.github.com/articles/dealing-with-line-endings
+######################################################################
+#
+# If you change a setting here,
+# you should also change .editorconfig
+#
+*.py diff=python text eol=lf whitespace="trailing-space,space-before-tab,tab-in-indent,blank-at-eof,tabwidth=4"
+*.yml text eol=lf whitespace="trailing-space,space-before-tab,tab-in-indent,blank-at-eof,tabwidth=2"

HACKING

@@ -1,8 +1,22 @@
-To run all tests, install the python-nose package and from the root of the
-project:
+Hacking
+=======
 
-    ./runtests.py
+Python versions
+---------------
 
+Tito supports Python versions 2.4 (RHEL 5) and up.
+See http://docs.python.org/dev/howto/pyporting.html
+and http://python3porting.com/differences.html
+for tips on writing portable Python code.
+
+
+Tests
+-----
+
+To run all tests, install the python-nose and python3-nose
+packages, then from the root of the project:
+
+    python  ./runtests.py
 
 
 When developing code for tito there are a couple ways you can test:
@@ -10,7 +24,9 @@ When developing code for tito there are a couple ways you can test:
 "bin/tito-dev" is a script that will run code from the local checkout
 rather than what is installed on the system.
 
-And of course, you can always use the installed tito to replace itself with a test build of the latest *committed* code in your git HEAD.
+And of course, you can always use the installed tito to replace
+itself with a test build of the latest *committed* code in your
+git HEAD.
 
     tito build --rpm --test -i
 
@@ -19,3 +35,20 @@ If you screw anything up inside tito itself, you can just:
     rpm -e tito
     yum install tito
 
+
+Code style
+----------
+
+Python3 does not allow mixing tabs and spaces for indentation.
+http://docs.python.org/3.3/reference/lexical_analysis.html
+
+You can force your editor to do the right thing by installing
+a plugin for your editor from http://editorconfig.org/#download
+
+For example, add the EditorConfig plugin for vim like this:
+
+    cd /tmp/
+    wget https://github.com/editorconfig/editorconfig-vim/archive/master.zip
+    unzip master.zip
+    mkdir ~/.vim
+    cp -r editorconfig-vim-master/* ~/.vim/