Improve caching prevention for avatar images

Closes #54.
Update install.xml (bumped to v0.9.2)
Add v0.9.2 to UMIL install file (no changes)
Update to MODX 1.2.6
Add github repo link to install.xml

New in MODX 1.2.6.
Add real name to install.xml

I've been out of the figurative closet for some time now
Fix MODX version in install.xml header
Regenerate install.xml using online MODX creator

It wasn't working before, but it should work now. The instructions are
the same, except that now the PHP install file field is being used, so
that AutoMOD will link to dynamo_mod_install.php after the rest of the
installation is complete.
List all copy instructions in install.xml

Incredibly tedious but now installing and uninstalling with AutoMOD
should work.
Fix jQuery include link in UCP

Forgot to fix this after updating to v1.9.1 in commit
7839661cfbc810b9371b042ecdcd13c82cddc6f4.
Update MOD to version 0.9.3