support url connections other than 'http'
don't download zip archives in tests, use zip archive from testData
- DebugAssertions.DEBUG is enabled for EAP / internal mode
- introduced / used ValueIterator class to be able to get file set associated with given value without hash map lookup with m.b. costly hash code calculation (IDEA-125200)
- during particular value loading and calculating merged data if given key has number of values more than threshold calculate / use direct mapping of fileId -> Value instead of traversing all values (thus removing O(NumberOfValues) per fileId)
duplicated "breakpoint reached" message for java breakpoints