Makefile: Replace root directory with relative path.

Since we use two different SCMs, we can not rely on one of them.
Template handler: Add support for multilanguage tag parameters.

Using `cms:constants` as tag parameter developer is able now to specify
which parameters are language constants. This is handy for use in `img`
tags for `alt` parameter as one example.
Template handler: Fix bug with function calling.
Template handler: Change to singular for cms:constants.
Merge branch 'master' of hg::/home/meaneye/Development/Workspace/PHP/Caracal/Source