Summary
-------

This feature introduces three String instance methods for removal
of Unicode white space from the beginning and end of a string.

Problem
-------

String::trim has existed from early days of Java when Unicode had not
fully evolved to the standard we widely use today.

The definition of space used by String::trim is any code point less than
or equal to the space code point (\u0020), commonly referred to as ASCII 
or ISO control characters.

Unicode-aware trimming routines should use Character::isWhitespace(int).

Additionally, developers have not been able to specifically remove
indentation white space or to specifically remove trailing white space.

Solution
--------

Introduce trimming methods that are Unicode white space aware
and provide additional control of leading only or trailing only.

Specification
-------------

```
   /**
     * Returns a string whose value is this string, with all leading
     * and trailing {@link Character#isWhitespace(int) white space}
     * removed.
     * <p>
     * If this {@code String} object represents an empty string,
     * or if all code points in this string are
     * {@link Character#isWhitespace(int) white space}, then an empty string
     * is returned.
     * <p>
     * Otherwise, returns a substring of this string beginning with the first
     * code point that is not a {@link Character#isWhitespace(int) white space}
     * up to and including the last code point that is not a 
     * {@link Character#isWhitespace(int) white space}.
     * <p>
     * This method may be used to strip
     * {@link Character#isWhitespace(int) white space} from
     * the beginning and end of a string.
     *
     * @return  a string whose value is this string, with all leading
     *          and trailing white space removed
     *
     * @see Character#isWhitespace(int)
     *
     * @since 11
     */
    public String strip() {

    /**
     * Returns a string whose value is this string, with all leading
     * {@link Character#isWhitespace(int) white space} removed.
     * <p>
     * If this {@code String} object represents an empty string,
     * or if all code points in this string are
     * {@link Character#isWhitespace(int) white space}, then an empty string
     * is returned.
     * <p>
     * Otherwise, returns a substring of this string beginning with the first
     * code point that is not a {@link Character#isWhitespace(int) white space}
     * up to to and including the last code point of this string.
     * <p>
     * This method may be used to trim
     * {@link Character#isWhitespace(int) white space} from
     * the beginning of a string.
     *
     * @return  a string whose value is this string, with all leading white
     *          space removed
     *
     * @see Character#isWhitespace(int)
     *
     * @since 11
     */
    public String stripLeading() {

    /**
     * Returns a string whose value is this string, with all trailing
     * {@link Character#isWhitespace(int) white space} removed.
     * <p>
     * If this {@code String} object represents an empty string,
     * or if all characters in this string are
     * {@link Character#isWhitespace(int) white space}, then an empty string
     * is returned.
     * <p>
     * Otherwise, returns a substring of this string beginning with the first
     * code point of this string up to and including the last code point
     * that is not a  {@link Character#isWhitespace(int) white space}.
     * <p>
     * This method may be used to trim
     * {@link Character#isWhitespace(int) white space} from
     * the end of a string.
     *
     * @return  a string whose value is this string, with all trailing white
     *          space removed
     *
     * @see Character#isWhitespace(int)
     *
     * @since 11
     */
    public String stripTrailing() {

```