Add lodash which can be accessed with _.
Move lodash to arethusa.core

Test files typically don't get the arethusa module, but only the core,
so it's better to have it there.
Start with arethusa.util module
Remove global var arethusaGenerators
Get rid of global var arethusaClasses

Use the `commons` service of `arethusa.util` instead.
Remove global var arethusaLogger

Use `logger` of `arethusa.util` instead.
Start to move arethusaUtil
Merge pull request #456 from latin-language-toolkit/lodash

Use lodash - remove global variables. Fixes #441 & fixes #501
Throw out obsolete configuration files

Closes #505
Merge pull request #506 from latin-language-toolkit/conf_cleanup

Throw out obsolete configuration files
Make cite definition more robust
Natively support constituents
Update retrievers for new sentence syntax
Temporary fix in language settings
Start conf file for Constituent demo
Start with ConstituentTreebankRetriever
First attempt at parsing morphology
Update jr config - use correct morph
Experiment with depTrees out of jr documents
Properly handle token ids in ConstTbRetriever