Javadoc and tests relevant to Unicode in PythonInterpreter.

Makes trivial (format only) changes to Java code and adds Javadoc clarifying the current behaviour of PythonInterpreter and its subclasses with respect to Unicode programs and Reader/Writer streams used as sys.stdin/out/err. Tests are added to exercise the behaviour, including 3 skipped tests where features may be lacking.
Prevent String.atof() from accepting hex notation.

Fixes a test failure in test_float: float("0x3.p-1") to raise ValueError.
Fix float.__mod__ to conform to spec.

Fixes test failures in test_float by re-implementing using Java % and tweaks.
Fix float.__pow__ to conform to spec.

Fixes test failures in test_float, which can now revert to the CPython version.
Rationalise certain constants in PyFloat.
Fix str.__complex__() to accept all valid inputs.

Fixes a number of test failures in test_complex.
Formatting changes only, ahead of fixes to compiler/Module.java
Distinguish constants 0j and -0j when generating code.

Fixes a failure in test_complex: -0.0 and 0.0 are not the same constant.
Fixes comparison of complex with other types.

These were failures in test_complex.
Here endeth our need for a Jython-specific version of that.
Trivial formatting in math.java and cmath.java.

White space, line wraps, braces ... , ahead of substantive changes.
Tighten up on edge cases in math.acosh and atanh.

Amends test_math_jy to run the CPython test_math.MathTests again,
but expecting accurate results. Our acosh and atanh are re-written to
pass this stricter test. Loosely related to issue #2237.
Re-work cmath.sqrt.

Addresses certain test failures in test_cmath.CMathTests.test_specific_values,
part of issue #2237.
Correct overflow policy in complex.__abs__, math.hypot and cmath.polar

Fixes test failure polar0100 in test_cmath (issue #2237), and corrects and
adds a test for the comparable behaviour on complex and math.hypot.
Disable failing test of Unicode source in test_pythoninterpreter_jy.

Recently added tests aimed at exploring Unicode issues seem to
be fragile, so skip them for now.
Merge
Merge