Fix TaggerCharmTool FATAL messages
This patch will reuse the charmTagger-specific methods from master and fix several FATAL messages from TaggerCharmTool in the nightlies.
Some charm-tagger-specific development has been merged into the main flavour tagging package mistakenly. This is being reverted with this commit to use the correct, classic TaggerCharmTool version.
A note for @mschille: Additional dependencies of the getCharmDecayMode
in Analysis/ prevented me to move the getCharmDecayMode function into the TaggerCharmTool itself.