Attaching patch for complete conversion of Objects/unicodeobject.c.

Notes:
* maketrans() was already converted
* converting the lstrip, rstrip and strip methods required a small, non-trivial change to the code, since they used a common function for argument parsing
* the documentation for replace() now correctly reflects the actual function signature
* I rephrased some doc-strings where it was required, and in several places moved some of the text into parameter descriptions