[MERGE] per-user file properties

[Ian Clatworthy]

Talden wrote:

>>  How does this work on a repository basis? It is not a good idea to
>>  expect every user to configure this correctly and some files with the
>>  same pattern may have different line ending styles in different
>>  repositories. Storing the line ending style in the branch itself would
>>  be much better and more flexible. A property should be really tied to
>>  the file and not stored somewhere else. Otherwise when the file moves or
>>  the extension changes then the properties may also change.
> 
> I think this is a reasonable means of getting EOL transformation out
> to users promptly.

Given that there are strong opinions on the pros and cons of more
complete solutions, this is intended to be a starting point that:

* is powerful enough for us to build some important features on
* is easy for us to explain to early adopters of those features
* is low overhead in terms of performance and storage
* later solutions can be upwardly compatible with.

I openly acknowledge that this feature is far from perfect. Perfect will
take *much* longer if recent debates are any guide. Hopefully though,
this step is in the right direction and helps us find agreement on both
what the next step ought to be and how we can implement that next step
efficiently.

I suspect the key to gaining that agreement/knowledge is getting real
applications (like EOL support) built over the top of a first-cut
solution. Getting useful functionality available to users is therefore
my primary driver here.

Ian C.