0.70 release: new clamd and VBA macros decoding

The two major changes in this version are new "rock stable" thread manager in clamd and support for decoding MS Office VBA macros. Both of them have been implemented by Trog. Besides, there are many improvements and bugfixes (see ChangeLog for a complete list).
Special thanks to Dirk Mueller from kde.org for the code review and many bugfixes and cleanups.