Outdated documentation and build files

Many of these date back from Ye Olden Days of .NET 1.1.

CSharpBuilder/: Outdated Borland project files from 12 years ago, doesn't match the structure of the project nowadays.
docs/: Just the IRC RFC. Not needed, could be supplemented if need be.
API_CHANGE: Affects an ancient branch.
CHANGELOG: Very outdated, somewhat redundant with git log.
CREDITS: outdated, should be updated or use the copyright comment headers
FEATURES: outdated
README: project filesystem structure outdated
TODO: outdated, should be put into issues?

meebey / SmartIrc4net