[GiNaC-devel] Real and imaginary parts.

Dear GiNaCers, I have added the methods .real_part() and .imag_part() to the library for taking real and imaginary parts of expressions. Functions know how to take real and imaginary parts of themselves through two new function options. I did not add the required methods for this to all standard functions but the trigoniometric functions have been done. These new features are documented in the tutorial. Also, I noticed that the capitalization of words in section titles in the tutorial is inconsistent. I made this consistent by making all (except the first) words that are not names start with a lower case letter. Best, Chris