Test how we wrap long lines a bit
Rewrite quoteforpo() for performance

This way we only escape the whole string once. We now wrap the escaped
text, instead of escaping the wrapped text, which is closer to what
gettext does.
Allow up to 77 characters per line

Now that we wrap escaped text, this brings us even closer to how gettext
formats lines.
Update test to conform to msgcat

Tested with msgcat version 0.18.2
Fix broken test
Remove unused code
Remove unused code
Remove code for Python < 2.3
Remove customisation for '%'

Gettext doesn't really work this way (or not any more).
Add trailing spaces to chunks

This way we don't need to handle trailing spaces in pypo, which caused
us to go over the length limit in some cases.
Remove unneeded import
Simplify wrapline()

Now that our textwrap module does more what we want, we can simplify
how we call it substantially (this function is actually unneeded now).
Simply use the stdlib wrapper and replace regex

We only need a different regex, and this way we can use the stdlib
and get rid of our local copy of it.
Only replace the regex on the instance

Otherwise we change wrapping for all users of the textwrap module (such
as optparse, for example).
Rewrite quoteforpo()

This simplifies the code and fixes all unit tests we have now.
Remove unused import
An alternative construction of wrapper for Python < 2.6