Resolution for Issue #50

Resolution for Issue #50 (addressing a bug in NAnt 0.92) by ensuring that count of "asis" includes is considered as well (next to normal "includes") in the "copy" task; thus with this fix avoiding that a (referenced) file set with only "asis" includes might be (incorrectly) seen as empty... which in turn (in the un-patched code) would result in all files and sub-folders to be added to the file set.

The other commit is a simple fix of a typo spotted in the README.txt file, where two subheadings both used (incorrectly) "b."; fixed by setting "Building the Software" to use subheading "c."

Please note that I've not been able to build using the README.txt instructions... somehow .NET Framework SDKs are not recognized on my Windows 7 / VS2012 setup while using the instructions provided. However, using VS2012 directly I could make binaries and by manual copy-and-paste replacements confirm that a modified NAnt distribution would produce the desired result.