Update docs

[blurayne]

I'm no python expert, but default compilation didn't work.

I got following error:
Traceback (most recent call last):
File "./KeyboardLayoutEditor", line 64, in
import ParseXKB
File "/home/ctang/Sources/keyboardlayouteditor/ParseXKB.py", line 26, in
from XKBGrammarLexer import XKBGrammarLexer
File "/home/ctang/Sources/keyboardlayouteditor/XKBGrammarLexer.py", line 63, in
class XKBGrammarLexer(Lexer):
File "/home/ctang/Sources/keyboardlayouteditor/XKBGrammarLexer.py", line 66, in XKBGrammarLexer
antlr_version = version_str_to_tuple("3.1.2")
NameError: name 'version_str_to_tuple' is not defined

After having pip upgraded I had to use having read that For backward compatibility reasons, ANTLR 3.5.2 still generates code that uses ST v3 at parse-time
$ java -classpath antlr-3.5.2-complete.jar org.antlr.Tool *.g

That works again for ubuntu/yakkety.