revert "Platform: more accessible CaseInsensitiveStringHashingStrategy - available from StringUtil now";
get rid of trove deps from StringUtil
fix and deduplicate CharArrayUtil, introduce CharArrayExternalizable
ImmutableText implements CharArrayExternalizable
platform: async refresh rate limited
platform: PlatformUtils returned to the platform
junit version fixed for licenses (hamcrest has new BSD which is weaker than junit!)
include hamcrest-library-1.3 into junit (IDEA-119067)