Apply Android Studio inspections

* Remove invalid manifest entries
* Remove redundant finals
* Remove redundant semicolons
* Remove unnecessary boxing/unboxing
* Remove redundant type casts
* Remove redundant toString calls
* Replace StringBuilders with Strings
* Remove manual array operations
* Replace StringBuffer with StringBuilder
* Replace for with foreach
* Remove unused try/catch
* Remove unused collections
* Remove empty if statements
* Remove unused return values
* Remove redundant local variables
* Remove redundant assignments and unused variables
* Remove unused logo change
* Remove unused strings
* Fix string comparison
Update translations

* Slovenian (damir12)
* Hebrew (amititzhaki)
* French (mdubois)
* Remove unused translations