Re-formatted all code using clang-format.
Added clang-format config file used for formatting

via clang-format.

The clang-format config file keeps track of the formatting options
we decide on for formatting our MCell code. The committed version
has been used to as input to clang-format to re-format the complete
MCell source tree. To use the config file do

% cp clang-format.conf ~/.clang-config

Then use clang-format on any of your source files via

% clang-format -i <some_file.c>