Suppress "no such version" error when installing from non lib.haxe.org location

If you install from a zip file or a different repo, it tries to post stats to lib.haxe.org.
If the project or version you installed doesn't exist there, it throws an error.

This shouldn't be a show stopper
Slightly clearer feedback during selfupdate
Update JSON, bump version number, include ConvertXml.hx in packed library
Add schema.json from Zachary Dremann's gist

https://gist.github.com/Dr-Emann/5673379

My alterations:

 * Removed description as required (it's not)
 * Removed min lengths of 2, when they are 0
 * Changed minimum name length to 2 (does this apply to users also?)
 * Set additionalProperties to true (so people could extend it for their own needs)

Feel free to argue.  I still haven't added classPath yet.
Add classPath to schema
Cleaned up submission process.

It now lets you pick which user you are submitting as, and retry your
password if you get it wrong
Don't print "checkout NULL" when using git without specifying branch