- StringSegment, ICU4C:
* Moved to top icu namespace
* Compilation unit renamed to string_segment.
- NumberStringBuilder, C and J:
* Moved to main icu namespace
* Compilation unit renamed to formatted_string_builder
* Renamed class to FormattedStringBuilder
- Moves nextPosition logic of NumberStringBuilder to helper class
- Adds additional logic to NumberStringBuilder.
- Extends logic of number::impl::Field type.
- Adds tests for RBNF support.
- Adds tests from ftang's original PR.
- Wires up FormattedNumber[Range] in applicable languages.
- Adds new header files and tests, with minor cleanup to old tests.
- Adds code to guarantee terminating NUL in FormattedNumber[Range].
- Cleanup of API docs for inherited methods in FormattedNumber[Range].