Runtime/tarcmd: fixed a loop and a memory leak

Started on a XAR file system stream similar to what we have for TAR already.

IPRT: Added compression to the gzip VFS I/O stream class (RTZipGzipCompressIoStream) and implemented compression in the RTGzip example tool (testcase\RTGzip.exe).

Windows build fixes.

RTTar: Implemented simple extraction (-x).

IPRT: Initial implementation of rm. Missing interactivity. Not tested at all (later).

scm cleanups.

iprt/tarvfs: Rewrote the tar parser to deal with header sequences used by solaris, gnu and pax while being offline yesterday. Only GNU long link and long names are supported, but adding pax and solaris support is possible. This also resolves some of the ustar<space><space> vs. ustart<null>00 problems (the latter was not readable previously).

vfs/tar: symlink fixes.

tar: fixed bugs, listing output is identical to gnutar (when using --utc).

build fix

iprt: more tar code and vfs filesystem stream bugfixes.