Fixed bugs and edited inadequate configs
Added a new modifier LanguageCondeModifier
Fixed a wrong conditional expression
Fixed a typo
Merge branch 'DS-1777' of https://github.com/zuki/DSpace into DS-1777
fix arxiv BTE configuration
fix pubmed BTE configuration
fix crossref BTE configuration
fix 'BTE to DSpace' configuration
remove warning in LanguageCodeModifier
applied EKT-DS-1777