Blocks support into Stach

Stach is still a WIP, so not all stuff works, but I did fix a few issues, and most off all block support.

What are blocks?
The technique is based on "solid archiving" which both rar and 7z support (and which 7z even does by default).  It allows multiple files to be brought into one block and that entire block is packed as a whole, in stead of file by file. The most recent versions of the JCR6 library for C++ and C# do support a block system that is a bit similar to that technique. I brought this in, because there are in my games files that are mostly loaded together, and then this can save time as then only one block has to be loaded and unpacked in stead of many small ones. 

Stach, as a JCR6 viewer was up to now not fully supportive of this, as this technique has only be brought to JCR6 recently, so older compiled versions of Stach could crash upon reading a file in which this technique was used (first game to use it was Star Story (remake version)), and if you compiled Stach from source you could get a few funny effects. Neither were really desirable. This new version should cover this up more adequately.