Changes to TagProvider and build.xml

Hi,
I have made 2 rather major changes to MDR that may have impact on your 
code/build process:
1) I made most of the static methods in TagProvider to be non-static. 
This is to have better control over TagProvider's cache. Cached data now 
live only during the life of TagProvider's instance. This fixes bug 
earlier mentioned on this list by Holger. Note, that I didn't do the 
same with TagSupport as TagSupport is invoked only on metamodels that 
already have been instantiated and thus changes to them would be fatal 
anyway. (I am planning on implementing a freezing mechanism that will 
disable any changes to a metamodel if there exists an instance of it in 
the repository.)
2) MDRExplorer is now built using default task in build.xml. This means 
that you may have problem building MDR using default task if you don't 
have looks and naming modules built as MDRExplorer depends on these modules.
Martin